①. 由于各國管件標準化程度不同，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(zhi)管連接件(jian)的選擇

   a. 主(zhu)要根據管(guan)道(dao)的(de)(de)設(she)計溫度、設(she)計壓力、腐蝕余量(liang)等設(she)計條件確定(ding)的(de)(de)。分支(zhi)(zhi)的(de)(de)方法：對于低壓大直徑管(guan)則直接把(ba)分支(zhi)(zhi)管(guan)焊于主(zhu)管(guan)上，另外(wai)多數是利用分支(zhi)(zhi)管(guan)件進行分支(zhi)(zhi)。

   b. 當(dang)從主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)引出支管(guan)(guan)(guan)(guan)(guan)時，支管(guan)(guan)(guan)(guan)(guan)直徑(jing)(jing)與主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)直徑(jing)(jing)的比值大(da)于(yu)等(deng)于(yu)0.5時，采用(yong)(yong)異徑(jing)(jing)三通(tong)或(huo)等(deng)徑(jing)(jing)三通(tong)，當(dang)主(zhu)(zhu)支管(guan)(guan)(guan)(guan)(guan)為(wei)等(deng)徑(jing)(jing)時，應采用(yong)(yong)三通(tong)。GB50316 規定：公稱壓(ya)力(li)大(da)于(yu)或(huo)等(deng)于(yu)10MPa的管(guan)(guan)(guan)(guan)(guan)道(dao)，主(zhu)(zhu)支管(guan)(guan)(guan)(guan)(guan)為(wei)異徑(jing)(jing)時，不宜采用(yong)(yong)焊接(jie)支管(guan)(guan)(guan)(guan)(guan)，宜采用(yong)(yong)三通(tong)或(huo)在主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)上開孔并(bing)焊接(jie)支管(guan)(guan)(guan)(guan)(guan)臺。當(dang)主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)直徑(jing)(jing)大(da)于(yu)DN65而支管(guan)(guan)(guan)(guan)(guan)直徑(jing)(jing)為(wei)DN40及以下時，根據(ju)設計壓(ya)力(li)的大(da)小，采用(yong)(yong)支管(guan)(guan)(guan)(guan)(guan)臺或(huo)半管(guan)(guan)(guan)(guan)(guan)接(jie)頭。

   c. 主(zhu)(zhu)管(guan)(guan)直(zhi)徑(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)DN50時，支(zhi)(zhi)管(guan)(guan)小(xiao)于(yu)(yu)(yu)(yu)主(zhu)(zhu)管(guan)(guan)，則用異(yi)徑(jing)(jing)三通(tong)或等徑(jing)(jing)三通(tong)加(jia)異(yi)徑(jing)(jing)短管(guan)(guan)。設(she)計(ji)壓力(li)等于(yu)(yu)(yu)(yu)或大于(yu)(yu)(yu)(yu)2.0MPa、設(she)計(ji)溫度超過250℃以及支(zhi)(zhi)管(guan)(guan)與(yu)主(zhu)(zhu)管(guan)(guan)公(gong)稱直(zhi)徑(jing)(jing)之(zhi)比大于(yu)(yu)(yu)(yu)0.8，或承(cheng)(cheng)受機械振動、壓力(li)脈動和溫度急劇變(bian)化的(de)(de)管(guan)(guan)道(dao)分(fen)支(zhi)(zhi)，應采用等徑(jing)(jing)異(yi)徑(jing)(jing)三通(tong)；公(gong)稱直(zhi)徑(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)或等于(yu)(yu)(yu)(yu)40mm的(de)(de)管(guan)(guan)道(dao)，應采用承(cheng)(cheng)插(cha)焊(han)(han)(han)（或螺紋）鍛制三通(tong)；公(gong)稱直(zhi)徑(jing)(jing)等于(yu)(yu)(yu)(yu)或大于(yu)(yu)(yu)(yu)50mm的(de)(de)管(guan)(guan)道(dao)，應采用對(dui)焊(han)(han)(han)三通(tong)、對(dui)焊(han)(han)(han)加(jia)強(qiang)管(guan)(guan)接頭(tou)(tou)(tou)（對(dui)焊(han)(han)(han)支(zhi)(zhi)管(guan)(guan)臺(tai)）或嵌入式（鞍型(xing)）支(zhi)(zhi)管(guan)(guan)接頭(tou)(tou)(tou)。支(zhi)(zhi)管(guan)(guan)通(tong)過加(jia)強(qiang)管(guan)(guan)接頭(tou)(tou)(tou)（支(zhi)(zhi)管(guan)(guan)臺(tai)）與(yu)主(zhu)(zhu)管(guan)(guan)連接是指(zhi)將(jiang)一(yi)個螺紋、承(cheng)(cheng)插(cha)焊(han)(han)(han)或對(dui)焊(han)(han)(han)的(de)(de)管(guan)(guan)接頭(tou)(tou)(tou)或半管(guan)(guan)接頭(tou)(tou)(tou)（支(zhi)(zhi)管(guan)(guan)臺(tai)）直(zhi)接焊(han)(han)(han)于(yu)(yu)(yu)(yu)主(zhu)(zhu)管(guan)(guan)上而制成(cheng)，螺紋、承(cheng)(cheng)插(cha)焊(han)(han)(han)支(zhi)(zhi)管(guan)(guan)臺(tai)用于(yu)(yu)(yu)(yu)直(zhi)徑(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)等于(yu)(yu)(yu)(yu)DN40（NPS1/2）的(de)(de)支(zhi)(zhi)管(guan)(guan)連接。螺紋、承(cheng)(cheng)插(cha)焊(han)(han)(han)支(zhi)(zhi)管(guan)(guan)臺(tai)在任(ren)何情況下其額定等級應大于(yu)(yu)(yu)(yu)等于(yu)(yu)(yu)(yu)20001b。

   d. 其他(ta)支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)可用(yong)直接(jie)(jie)(jie)焊(han)接(jie)(jie)(jie)，但必(bi)須(xu)經校核后明確是否增加(jia)(jia)補強。直接(jie)(jie)(jie)焊(han)接(jie)(jie)(jie)在主(zhu)管(guan)上(shang)的(de)(de)(de)(de)支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)，不宜用(yong)于有機械振動、壓力脈(mo)動和溫度(du)急劇變化的(de)(de)(de)(de)部位(wei)及設計溫度(du)超過425℃的(de)(de)(de)(de)管(guan)道(dao)，當支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)處承受由于支(zhi)(zhi)管(guan)熱(re)變形、外載荷(he)及支(zhi)(zhi)架位(wei)移(yi)等引起的(de)(de)(de)(de)應力時(shi)，應對附(fu)加(jia)(jia)載荷(he)在支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)處產生的(de)(de)(de)(de)影響進行分(fen)析并采(cai)取(qu)必(bi)要的(de)(de)(de)(de)加(jia)(jia)強措(cuo)施。

   e. 實際設計過程中(zhong)，主(zhu)(zhu)要(yao)依據管(guan)(guan)(guan)(guan)(guan)道(dao)等(deng)(deng)級中(zhong)已經確(que)定(ding)的(de)(de)法(fa)蘭壓(ya)力(li)等(deng)(deng)級或公(gong)稱(cheng)壓(ya)力(li)（PN）來選(xuan)用(yong)(yong)支管(guan)(guan)(guan)(guan)(guan)連(lian)(lian)接件(jian)(jian)。一般情況下，當法(fa)蘭的(de)(de)公(gong)稱(cheng)壓(ya)力(li)PN≤2.5MPa時(shi)，支管(guan)(guan)(guan)(guan)(guan)直接焊(han)(han)(han)接在主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)上；當PN≥4.0MPa時(shi)，則(ze)根(gen)據主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)支管(guan)(guan)(guan)(guan)(guan)公(gong)稱(cheng)直徑(jing)的(de)(de)不(bu)同按(an)對(dui)焊(han)(han)(han)三通、對(dui)焊(han)(han)(han)加(jia)強(qiang)(qiang)管(guan)(guan)(guan)(guan)(guan)接頭(tou)(tou)、承插焊(han)(han)(han)或螺(luo)紋(wen)連(lian)(lian)接三通、承插焊(han)(han)(han)或螺(luo)紋(wen)加(jia)強(qiang)(qiang)管(guan)(guan)(guan)(guan)(guan)接頭(tou)(tou)的(de)(de)順序選(xuan)用(yong)(yong)。值得注(zhu)意的(de)(de)是在確(que)定(ding)支管(guan)(guan)(guan)(guan)(guan)連(lian)(lian)接件(jian)(jian)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)時(shi)，應根(gen)據管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)等(deng)(deng)強(qiang)(qiang)度(du)的(de)(de)原則(ze)以(yi)及管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)與(yu)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)連(lian)(lian)接方式而定(ding)。例(li)如，當管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)采用(yong)(yong)對(dui)焊(han)(han)(han)連(lian)(lian)接時(shi)，管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)應一致；而當管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)采用(yong)(yong)承插焊(han)(han)(han)或螺(luo)紋(wen)連(lian)(lian)接時(shi)，標(biao)準的(de)(de)承插焊(han)(han)(han)和螺(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)只(zhi)有Sch80、Sch60、XXS，最低(di)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)是Sch80，也(ye)就(jiu)是說只(zhi)要(yao)當承插焊(han)(han)(han)或螺(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)所(suo)連(lian)(lian)接的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)不(bu)大(da)于(yu)(yu)Sch80時(shi)，承插焊(han)(han)(han)或螺(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)選(xuan)Sch80。而當所(suo)連(lian)(lian)接的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)大(da)于(yu)(yu)Sch80時(shi)，承插焊(han)(han)(han)或螺(luo)紋(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)(jian)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就(jiu)選(xuan)Sch60或XXS。

   f. 當對焊三(san)通(tong)主管(guan)(guan)、支管(guan)(guan)所連接的管(guan)(guan)子的管(guan)(guan)子表號(hao)(hao)不(bu)同時(shi)，應注意三(san)通(tong)主管(guan)(guan)、支管(guan)(guan)端部的管(guan)(guan)子表號(hao)(hao)應分(fen)別與其所連接的管(guan)(guan)子的管(guan)(guan)子表號(hao)(hao)相同，這樣就非常方便(bian)管(guan)(guan)道施工(gong)，管(guan)(guan)件不(bu)必現(xian)場再打坡口。

 ③. 分支管與主(zhu)管連接的管件選(xuan)擇見表16.71。