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. 支管連接件(jian)的選擇(ze)

   a. 主要(yao)根(gen)據(ju)管(guan)(guan)(guan)道(dao)的(de)設(she)計(ji)溫(wen)度、設(she)計(ji)壓力(li)、腐(fu)蝕(shi)余量(liang)等(deng)設(she)計(ji)條件(jian)確定(ding)的(de)。分支(zhi)的(de)方法：對于低壓大直徑管(guan)(guan)(guan)則直接把分支(zhi)管(guan)(guan)(guan)焊于主管(guan)(guan)(guan)上，另外多(duo)數是利用分支(zhi)管(guan)(guan)(guan)件(jian)進(jin)行分支(zhi)。

   b. 當(dang)從主(zhu)管(guan)(guan)(guan)引出支(zhi)管(guan)(guan)(guan)時(shi)，支(zhi)管(guan)(guan)(guan)直徑(jing)(jing)(jing)與(yu)主(zhu)管(guan)(guan)(guan)直徑(jing)(jing)(jing)的比值大(da)(da)于(yu)(yu)等(deng)(deng)于(yu)(yu)0.5時(shi)，采用異徑(jing)(jing)(jing)三(san)通(tong)或等(deng)(deng)徑(jing)(jing)(jing)三(san)通(tong)，當(dang)主(zhu)支(zhi)管(guan)(guan)(guan)為等(deng)(deng)徑(jing)(jing)(jing)時(shi)，應采用三(san)通(tong)。GB50316 規定(ding)：公稱壓(ya)(ya)力大(da)(da)于(yu)(yu)或等(deng)(deng)于(yu)(yu)10MPa的管(guan)(guan)(guan)道，主(zhu)支(zhi)管(guan)(guan)(guan)為異徑(jing)(jing)(jing)時(shi)，不宜(yi)采用焊接(jie)支(zhi)管(guan)(guan)(guan)，宜(yi)采用三(san)通(tong)或在(zai)主(zhu)管(guan)(guan)(guan)上(shang)開孔(kong)并焊接(jie)支(zhi)管(guan)(guan)(guan)臺。當(dang)主(zhu)管(guan)(guan)(guan)直徑(jing)(jing)(jing)大(da)(da)于(yu)(yu)DN65而支(zhi)管(guan)(guan)(guan)直徑(jing)(jing)(jing)為DN40及以下(xia)時(shi)，根據(ju)設(she)計(ji)壓(ya)(ya)力的大(da)(da)小，采用支(zhi)管(guan)(guan)(guan)臺或半管(guan)(guan)(guan)接(jie)頭。

   c. 主管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)小(xiao)于DN50時，支(zhi)管(guan)(guan)(guan)(guan)(guan)小(xiao)于主管(guan)(guan)(guan)(guan)(guan)，則(ze)用(yong)異徑(jing)(jing)三(san)通(tong)或等(deng)(deng)徑(jing)(jing)三(san)通(tong)加(jia)異徑(jing)(jing)短(duan)管(guan)(guan)(guan)(guan)(guan)。設(she)計壓力等(deng)(deng)于或大(da)(da)(da)于2.0MPa、設(she)計溫度超(chao)過(guo)250℃以及支(zhi)管(guan)(guan)(guan)(guan)(guan)與主管(guan)(guan)(guan)(guan)(guan)公(gong)稱(cheng)直(zhi)徑(jing)(jing)之比(bi)大(da)(da)(da)于0.8，或承(cheng)(cheng)受(shou)機械振動(dong)、壓力脈動(dong)和溫度急劇變化的管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)分支(zhi)，應采(cai)用(yong)等(deng)(deng)徑(jing)(jing)異徑(jing)(jing)三(san)通(tong)；公(gong)稱(cheng)直(zhi)徑(jing)(jing)小(xiao)于或等(deng)(deng)于40mm的管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)，應采(cai)用(yong)承(cheng)(cheng)插焊(han)(han)(han)(han)(han)（或螺(luo)紋）鍛制三(san)通(tong)；公(gong)稱(cheng)直(zhi)徑(jing)(jing)等(deng)(deng)于或大(da)(da)(da)于50mm的管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)，應采(cai)用(yong)對(dui)焊(han)(han)(han)(han)(han)三(san)通(tong)、對(dui)焊(han)(han)(han)(han)(han)加(jia)強管(guan)(guan)(guan)(guan)(guan)接頭(tou)（對(dui)焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)(guan)臺）或嵌入(ru)式(shi)（鞍(an)型）支(zhi)管(guan)(guan)(guan)(guan)(guan)接頭(tou)。支(zhi)管(guan)(guan)(guan)(guan)(guan)通(tong)過(guo)加(jia)強管(guan)(guan)(guan)(guan)(guan)接頭(tou)（支(zhi)管(guan)(guan)(guan)(guan)(guan)臺）與主管(guan)(guan)(guan)(guan)(guan)連(lian)接是(shi)指將(jiang)一個螺(luo)紋、承(cheng)(cheng)插焊(han)(han)(han)(han)(han)或對(dui)焊(han)(han)(han)(han)(han)的管(guan)(guan)(guan)(guan)(guan)接頭(tou)或半管(guan)(guan)(guan)(guan)(guan)接頭(tou)（支(zhi)管(guan)(guan)(guan)(guan)(guan)臺）直(zhi)接焊(han)(han)(han)(han)(han)于主管(guan)(guan)(guan)(guan)(guan)上(shang)而制成(cheng)，螺(luo)紋、承(cheng)(cheng)插焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)(guan)臺用(yong)于直(zhi)徑(jing)(jing)小(xiao)于等(deng)(deng)于DN40（NPS1/2）的支(zhi)管(guan)(guan)(guan)(guan)(guan)連(lian)接。螺(luo)紋、承(cheng)(cheng)插焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)(guan)臺在(zai)任何情況下其(qi)額定(ding)等(deng)(deng)級應大(da)(da)(da)于等(deng)(deng)于20001b。

   d. 其他支(zhi)管(guan)連(lian)(lian)接(jie)(jie)可用直(zhi)接(jie)(jie)焊接(jie)(jie)，但(dan)必(bi)須經校核(he)后(hou)明(ming)確是否增加(jia)補強。直(zhi)接(jie)(jie)焊接(jie)(jie)在(zai)主(zhu)管(guan)上的(de)(de)支(zhi)管(guan)連(lian)(lian)接(jie)(jie)，不宜用于(yu)有機(ji)械振動、壓力(li)脈動和(he)溫(wen)度急劇變化的(de)(de)部(bu)位及設計溫(wen)度超過425℃的(de)(de)管(guan)道，當支(zhi)管(guan)連(lian)(lian)接(jie)(jie)處承(cheng)受由于(yu)支(zhi)管(guan)熱(re)變形、外載(zai)荷(he)(he)及支(zhi)架位移等引起的(de)(de)應(ying)力(li)時，應(ying)對附(fu)加(jia)載(zai)荷(he)(he)在(zai)支(zhi)管(guan)連(lian)(lian)接(jie)(jie)處產生的(de)(de)影響(xiang)進行(xing)分析并采取(qu)必(bi)要的(de)(de)加(jia)強措施。

   e. 實(shi)際設計過程中(zhong)，主要依據(ju)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)道等級(ji)中(zhong)已經確(que)定的(de)(de)(de)法(fa)蘭壓力(li)等級(ji)或公(gong)稱壓力(li)（PN）來選(xuan)(xuan)用(yong)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)(jie)(jie)件(jian)(jian)(jian)(jian)。一般情況下(xia)，當法(fa)蘭的(de)(de)(de)公(gong)稱壓力(li)PN≤2.5MPa時(shi)，支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)直接(jie)(jie)(jie)焊(han)接(jie)(jie)(jie)在主管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)上；當PN≥4.0MPa時(shi)，則根據(ju)主管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)公(gong)稱直徑的(de)(de)(de)不(bu)同按(an)對(dui)焊(han)三(san)(san)通、對(dui)焊(han)加強(qiang)(qiang)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)(jie)頭(tou)、承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋連(lian)接(jie)(jie)(jie)三(san)(san)通、承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋加強(qiang)(qiang)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)(jie)頭(tou)的(de)(de)(de)順序選(xuan)(xuan)用(yong)。值得注意(yi)的(de)(de)(de)是(shi)在確(que)定支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)(jie)(jie)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)時(shi)，應根據(ju)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)等強(qiang)(qiang)度的(de)(de)(de)原(yuan)則以及管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)與管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)連(lian)接(jie)(jie)(jie)方式而(er)(er)定。例(li)如，當管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)采用(yong)對(dui)焊(han)連(lian)接(jie)(jie)(jie)時(shi)，管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)應一致；而(er)(er)當管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)采用(yong)承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋連(lian)接(jie)(jie)(jie)時(shi)，標準的(de)(de)(de)承(cheng)插(cha)焊(han)和螺(luo)(luo)(luo)紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(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)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就是(shi)Sch80，也就是(shi)說(shuo)只(zhi)要當承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)所(suo)連(lian)接(jie)(jie)(jie)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)不(bu)大于Sch80時(shi)，承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就選(xuan)(xuan)Sch80。而(er)(er)當所(suo)連(lian)接(jie)(jie)(jie)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)大于Sch80時(shi)，承(cheng)插(cha)焊(han)或螺(luo)(luo)(luo)紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表(biao)號(hao)就選(xuan)(xuan)Sch60或XXS。

   f. 當(dang)對焊三通主(zhu)管(guan)(guan)、支管(guan)(guan)所(suo)連(lian)接的管(guan)(guan)子(zi)的管(guan)(guan)子(zi)表號(hao)不同時，應(ying)注(zhu)意三通主(zhu)管(guan)(guan)、支管(guan)(guan)端(duan)部的管(guan)(guan)子(zi)表號(hao)應(ying)分別與其所(suo)連(lian)接的管(guan)(guan)子(zi)的管(guan)(guan)子(zi)表號(hao)相(xiang)同，這樣就非(fei)常方便管(guan)(guan)道施工(gong)，管(guan)(guan)件不必現(xian)場(chang)再打坡(po)口。

 ③. 分支(zhi)管與(yu)主管連(lian)接的管件(jian)選擇見表16.71。