球墨鑄(zhu)鐵管配件承(cheng)插單(dan)支(zhi)承(cheng)三通(tong)(tong)三通(tong)(tong)只有兩(liang)種,等徑三通(tong)(tong)和異徑三通(tong)(tong)。等徑三通(tong)(tong)就(jiu)是三個(ge)(ge)口一(yi)樣大小(xiao);異徑三通(tong)(tong)就(jiu)是一(yi)段主管加上(shang)一(yi)個(ge)(ge)小(xiao)的(de)分支(zhi)管,顯然,兩(liang)個(ge)(ge)大的(de)尺寸是主管,中(zhong)間(jian)接出來的(de)小(xiao)尺寸就(jiu)是支(zhi)管你所說的(de)那種比如是不存在的(de),標準產品的(de)三通(tong)(tong)只能是中(zhong)間(jian)的(de)那個(ge)(ge)接口變化尺寸,要在主管上(shang)再(zai)變尺寸就(jiu)接大小(xiao)頭。