①. 由于各國管件(jian)標準化程度不同，分支管連接方式及管件的選擇也不盡相同。一般情況下，支管連接多采用成形支管連接件、焊接的引出口連接件以及支管直接焊接在主管上等連接形式。值得注意的是選用支管直接焊接在主管上這一種連接形式，要核算管子是否需要補強。補強方法參見SH 3059《石油化工管道設計器材選用通則》、GB50316《工業金屬管道設計規范》的規定。
②. 支管連(lian)接(jie)件的選擇(ze)
a. 主要根據管(guan)(guan)道(dao)的設(she)(she)計溫度(du)、設(she)(she)計壓力(li)、腐(fu)蝕余量(liang)等設(she)(she)計條件確定的。分(fen)支的方法(fa)：對于低壓大直徑管(guan)(guan)則(ze)直接把(ba)分(fen)支管(guan)(guan)焊于主管(guan)(guan)上，另外(wai)多(duo)數是利用分(fen)支管(guan)(guan)件進(jin)行(xing)分(fen)支。
b. 當(dang)從(cong)主(zhu)(zhu)管(guan)(guan)引出支(zhi)(zhi)管(guan)(guan)時(shi)(shi)，支(zhi)(zhi)管(guan)(guan)直徑(jing)與主(zhu)(zhu)管(guan)(guan)直徑(jing)的(de)比值大于等(deng)于0.5時(shi)(shi)，采用(yong)異(yi)徑(jing)三通(tong)(tong)或等(deng)徑(jing)三通(tong)(tong)，當(dang)主(zhu)(zhu)支(zhi)(zhi)管(guan)(guan)為(wei)等(deng)徑(jing)時(shi)(shi)，應采用(yong)三通(tong)(tong)。GB50316 規定：公稱壓力大于或等(deng)于10MPa的(de)管(guan)(guan)道，主(zhu)(zhu)支(zhi)(zhi)管(guan)(guan)為(wei)異(yi)徑(jing)時(shi)(shi)，不宜采用(yong)焊接(jie)支(zhi)(zhi)管(guan)(guan)，宜采用(yong)三通(tong)(tong)或在主(zhu)(zhu)管(guan)(guan)上開(kai)孔并焊接(jie)支(zhi)(zhi)管(guan)(guan)臺。當(dang)主(zhu)(zhu)管(guan)(guan)直徑(jing)大于DN65而支(zhi)(zhi)管(guan)(guan)直徑(jing)為(wei)DN40及以下時(shi)(shi)，根據設(she)計壓力的(de)大小，采用(yong)支(zhi)(zhi)管(guan)(guan)臺或半管(guan)(guan)接(jie)頭。
c. 主(zhu)管(guan)(guan)(guan)直徑(jing)(jing)小于(yu)(yu)(yu)DN50時(shi)，支(zhi)管(guan)(guan)(guan)小于(yu)(yu)(yu)主(zhu)管(guan)(guan)(guan)，則用(yong)異徑(jing)(jing)三(san)通或(huo)(huo)(huo)等(deng)(deng)(deng)徑(jing)(jing)三(san)通加異徑(jing)(jing)短管(guan)(guan)(guan)。設(she)計壓力(li)(li)等(deng)(deng)(deng)于(yu)(yu)(yu)或(huo)(huo)(huo)大(da)(da)于(yu)(yu)(yu)2.0MPa、設(she)計溫度(du)超過(guo)250℃以(yi)及支(zhi)管(guan)(guan)(guan)與主(zhu)管(guan)(guan)(guan)公(gong)(gong)稱直徑(jing)(jing)之比大(da)(da)于(yu)(yu)(yu)0.8，或(huo)(huo)(huo)承(cheng)受機械(xie)振動(dong)、壓力(li)(li)脈動(dong)和溫度(du)急(ji)劇(ju)變化的管(guan)(guan)(guan)道(dao)分支(zhi)，應(ying)采(cai)用(yong)等(deng)(deng)(deng)徑(jing)(jing)異徑(jing)(jing)三(san)通；公(gong)(gong)稱直徑(jing)(jing)小于(yu)(yu)(yu)或(huo)(huo)(huo)等(deng)(deng)(deng)于(yu)(yu)(yu)40mm的管(guan)(guan)(guan)道(dao)，應(ying)采(cai)用(yong)承(cheng)插焊(han)(han)（或(huo)(huo)(huo)螺(luo)紋(wen)）鍛制三(san)通；公(gong)(gong)稱直徑(jing)(jing)等(deng)(deng)(deng)于(yu)(yu)(yu)或(huo)(huo)(huo)大(da)(da)于(yu)(yu)(yu)50mm的管(guan)(guan)(guan)道(dao)，應(ying)采(cai)用(yong)對(dui)焊(han)(han)三(san)通、對(dui)焊(han)(han)加強管(guan)(guan)(guan)接(jie)頭(tou)(tou)（對(dui)焊(han)(han)支(zhi)管(guan)(guan)(guan)臺）或(huo)(huo)(huo)嵌入(ru)式(shi)（鞍(an)型）支(zhi)管(guan)(guan)(guan)接(jie)頭(tou)(tou)。支(zhi)管(guan)(guan)(guan)通過(guo)加強管(guan)(guan)(guan)接(jie)頭(tou)(tou)（支(zhi)管(guan)(guan)(guan)臺）與主(zhu)管(guan)(guan)(guan)連(lian)接(jie)是(shi)指將一個螺(luo)紋(wen)、承(cheng)插焊(han)(han)或(huo)(huo)(huo)對(dui)焊(han)(han)的管(guan)(guan)(guan)接(jie)頭(tou)(tou)或(huo)(huo)(huo)半管(guan)(guan)(guan)接(jie)頭(tou)(tou)（支(zhi)管(guan)(guan)(guan)臺）直接(jie)焊(han)(han)于(yu)(yu)(yu)主(zhu)管(guan)(guan)(guan)上而制成，螺(luo)紋(wen)、承(cheng)插焊(han)(han)支(zhi)管(guan)(guan)(guan)臺用(yong)于(yu)(yu)(yu)直徑(jing)(jing)小于(yu)(yu)(yu)等(deng)(deng)(deng)于(yu)(yu)(yu)DN40（NPS1/2）的支(zhi)管(guan)(guan)(guan)連(lian)接(jie)。螺(luo)紋(wen)、承(cheng)插焊(han)(han)支(zhi)管(guan)(guan)(guan)臺在(zai)任何情況下其(qi)額定等(deng)(deng)(deng)級應(ying)大(da)(da)于(yu)(yu)(yu)等(deng)(deng)(deng)于(yu)(yu)(yu)20001b。
d. 其他支(zhi)管連接(jie)(jie)可用(yong)直接(jie)(jie)焊(han)(han)接(jie)(jie)，但必須經校核后明確是否增加(jia)(jia)補(bu)強(qiang)(qiang)。直接(jie)(jie)焊(han)(han)接(jie)(jie)在主管上的支(zhi)管連接(jie)(jie)，不宜用(yong)于有機械(xie)振動、壓力脈動和(he)溫度急劇變化的部位及設計溫度超過425℃的管道(dao)，當支(zhi)管連接(jie)(jie)處承受由于支(zhi)管熱變形、外載荷(he)及支(zhi)架(jia)位移(yi)等引(yin)起(qi)的應力時，應對附加(jia)(jia)載荷(he)在支(zhi)管連接(jie)(jie)處產生的影響進(jin)行分析并采取必要的加(jia)(jia)強(qiang)(qiang)措施。
e. 實際設計過程(cheng)中，主要(yao)依據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)(guan)道等級(ji)中已經確定的(de)(de)(de)(de)(de)(de)法(fa)(fa)蘭壓(ya)(ya)力(li)等級(ji)或(huo)公稱(cheng)壓(ya)(ya)力(li)（PN）來選用支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)連(lian)(lian)(lian)接(jie)(jie)(jie)件(jian)(jian)。一般情況下，當(dang)(dang)法(fa)(fa)蘭的(de)(de)(de)(de)(de)(de)公稱(cheng)壓(ya)(ya)力(li)PN≤2.5MPa時(shi)(shi)(shi)，支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)直(zhi)接(jie)(jie)(jie)焊(han)(han)(han)(han)接(jie)(jie)(jie)在(zai)主管(guan)(guan)(guan)(guan)(guan)(guan)上；當(dang)(dang)PN≥4.0MPa時(shi)(shi)(shi)，則(ze)根據(ju)(ju)主管(guan)(guan)(guan)(guan)(guan)(guan)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)公稱(cheng)直(zhi)徑的(de)(de)(de)(de)(de)(de)不同按(an)對(dui)焊(han)(han)(han)(han)三通、對(dui)焊(han)(han)(han)(han)加強管(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)(jie)頭、承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)連(lian)(lian)(lian)接(jie)(jie)(jie)三通、承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)加強管(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)(jie)頭的(de)(de)(de)(de)(de)(de)順序選用。值得注意的(de)(de)(de)(de)(de)(de)是在(zai)確定支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)連(lian)(lian)(lian)接(jie)(jie)(jie)件(jian)(jian)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)時(shi)(shi)(shi)，應(ying)根據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)等強度的(de)(de)(de)(de)(de)(de)原則(ze)以及管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)與管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)連(lian)(lian)(lian)接(jie)(jie)(jie)方(fang)式而定。例如(ru)，當(dang)(dang)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)采用對(dui)焊(han)(han)(han)(han)連(lian)(lian)(lian)接(jie)(jie)(jie)時(shi)(shi)(shi)，管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)應(ying)一致；而當(dang)(dang)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)采用承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)連(lian)(lian)(lian)接(jie)(jie)(jie)時(shi)(shi)(shi)，標準的(de)(de)(de)(de)(de)(de)承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)和螺(luo)(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)只(zhi)有Sch80、Sch60、XXS，最低的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)(jiu)是Sch80，也就(jiu)(jiu)是說只(zhi)要(yao)當(dang)(dang)承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)所連(lian)(lian)(lian)接(jie)(jie)(jie)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)不大于(yu)Sch80時(shi)(shi)(shi)，承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)(jiu)選Sch80。而當(dang)(dang)所連(lian)(lian)(lian)接(jie)(jie)(jie)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)大于(yu)Sch80時(shi)(shi)(shi)，承(cheng)(cheng)插(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)螺(luo)(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)(jiu)選Sch60或(huo)XXS。
f. 當對焊三(san)通(tong)主(zhu)管(guan)、支管(guan)所連接(jie)的(de)管(guan)子(zi)的(de)管(guan)子(zi)表(biao)號不(bu)同(tong)時(shi)，應(ying)注意三(san)通(tong)主(zhu)管(guan)、支管(guan)端(duan)部(bu)的(de)管(guan)子(zi)表(biao)號應(ying)分別與其所連接(jie)的(de)管(guan)子(zi)的(de)管(guan)子(zi)表(biao)號相同(tong)，這樣就非常(chang)方便管(guan)道施(shi)工，管(guan)件不(bu)必現(xian)場再打坡口。
③. 分支管(guan)(guan)(guan)與主管(guan)(guan)(guan)連接的管(guan)(guan)(guan)件選擇(ze)見表16.71。
