鉛管因質(zhi)軟且重(zhong),故經過搬運、裝(zhuang)卸之后一般(ban)均產(chan)生變形,所(suo)以鉛管在(zai)安裝(zhuang)前(qian)均應調直和校圓。
鉛(qian)(qian)管(guan)調直(zhi)時,鉛(qian)(qian)管(guan)應放在鋪有木板的平臺上用木榔頭輕(qing)輕(qing)敲(qiao)打(da)調直(zhi)。為了便于檢(jian)査和(he)操作,常(chang)把鉛(qian)(qian)管(guan)緊(jin)貼在角(jiao)鋼或槽鋼內側的翼(yi)上,根據管(guan)子和(he)型鋼的間(jian)隙拍打(da)調直(zhi)。
鉛管(guan)(guan)除調直(zhi)外,還需(xu)校(xiao)圓(yuan)(yuan)。直(zhi)徑(jing)大于(yu)DN50mm的(de)鉛管(guan)(guan)校(xiao)圓(yuan)(yuan),可用一根外徑(jing)小(xiao)于(yu)鉛管(guan)(guan)內徑(jing)的(de)鋼管(guan)(guan)(管(guan)(guan)端(duan)最好制(zhi)成一半球形封頭)穿(chuan)在鉛管(guan)(guan)內,并把(ba)鋼管(guan)(guan)的(de)兩(liang)端(duan)放在支撐架(jia)上, 然后用木錘敲打(da)鉛管(guan)(guan)被(bei)壓扁的(de)地(di)方,邊打(da)邊轉(zhuan)動管(guan)(guan)子(zi),直(zhi)到(dao)將管(guan)(guan)子(zi)校(xiao)圓(yuan)(yuan)為止。
鉛管(guan)校(xiao)圓(yuan)(yuan)的(de)(de)方(fang)法還有(you)用(yong)硬木制成(cheng)的(de)(de)外徑(jing)與(yu)鉛管(guan)內(nei)徑(jing)相同(tong)的(de)(de)圓(yuan)(yuan)柱形(xing)胎具,將頭部削圓(yuan)(yuan), 穿上繩(sheng)子(zi),用(yong)繩(sheng)將胎具拉進(jin)管(guan)內(nei),使變形(xing)部位(wei)隨胎具而撐(cheng)圓(yuan)(yuan)。
鉛管(guan)(guan)(guan)直徑不大于DN50mm的鉛管(guan)(guan)(guan)校圓,可將鉛管(guan)(guan)(guan)兩端堵(du)塞,在(zai)管(guan)(guan)(guan)內通入壓力為0.3~0.4MPa的壓縮空(kong)氣,然后用焊炬對壓扁的地方(fang)加熱,管(guan)(guan)(guan)內的壓縮空(kong)氣把(ba)管(guan)(guan)(guan)子脹圓,加熱時(shi),要注意使(shi)加熱部分受熱均勻,升(sheng)溫不要太快,當(dang)管(guan)(guan)(guan)子被脹圓時(shi),應立即停止加熱。

