盲板(ban)（Blind）、8字(zi)盲板(ban)（Spectacle Blind； Figure 8 Blind）、插板(ban)（Paddle Blank）以(yi)及墊環（Paddle Spacer），制造方法一般分三種(zhong)：鍛(duan)打、鑄鍛(duan)、中板(ban)割制。其中鍛(duan)打產品價(jia)格最(zui)高，中板(ban)次之，鑄鍛(duan)最(zui)低。而(er)質量是鍛(duan)打和中板(ban)的好(hao)，鑄鍛(duan)的要稍差些。盲板(ban)或“8”字(zi)盲板(ban)與(yu)閥(fa)門(men)相比，其關(guan)斷作用更可靠(kao)而(er)且更經濟。


  盲(mang)板(ban)、“8”字(zi)盲(mang)板(ban)、插板(ban)以及墊(dian)環(huan)都(dou)應(ying)有兩個和匹(pi)配法蘭(lan)同樣的(de)密封(feng)面。常用(yong)的(de)密封(feng)面包含平面、凹凸面、榫槽面和環(huan)連面。


  盲板（見圖4-15）用(yong)于起隔(ge)(ge)離(li)(li)、切斷作(zuo)用(yong)的，和(he)封(feng)頭、管帽所起的作(zuo)用(yong)是(shi)一樣的。由于其密封(feng)性能(neng)好，對于需要完全隔(ge)(ge)離(li)(li)的系(xi)統，一般(ban)都(dou)作(zuo)為可靠的隔(ge)(ge)離(li)(li)手段。盲板就是(shi)一個帶柄(bing)的實心的圓，用(yong)于通常狀況下處于隔(ge)(ge)離(li)(li)狀態的系(xi)統。盲板的有關(guan)標(biao)準，可參(can)見HG/T 20592～20635《鋼(gang)制(zhi)管法(fa)(fa)蘭、墊片、緊(jin)固(gu)件(jian)(jian)》和(he)ASME B16.5《管法(fa)(fa)蘭和(he)法(fa)(fa)蘭管件(jian)(jian)》。


圖 15.jpg


  8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)（見圖4-16），形狀像“8”字(zi)，一端是盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，另(ling)一端是節流(liu)環(huan)（墊(dian)(dian)環(huan)），但直徑與管(guan)道的(de)(de)管(guan)徑相同，并不(bu)起節流(liu)作用(yong)(yong)(yong)。8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，使用(yong)(yong)(yong)方便(bian)，需要(yao)隔離(li)時(shi)，使用(yong)(yong)(yong)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)端，需要(yao)正常操作時(shi)，使用(yong)(yong)(yong)節流(liu)環(huan)（墊(dian)(dian)環(huan)）端，同時(shi)也可(ke)用(yong)(yong)(yong)于(yu)(yu)填(tian)補管(guan)路(lu)上(shang)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)(de)安裝間(jian)隙。另(ling)一個特點就是標識明顯，易(yi)于(yu)(yu)辨認(ren)安裝狀態。主要(yao)用(yong)(yong)(yong)于(yu)(yu)小于(yu)(yu)等于(yu)(yu)DN600的(de)(de)管(guan)道系統。插(cha)板(ban)(ban)(ban)(ban)(ban)（見圖4-17）和墊(dian)(dian)環(huan)（見圖4-18）互為盲(mang)(mang)(mang)(mang)(mang)通，和8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)(de)作用(yong)(yong)(yong)類似，主要(yao)用(yong)(yong)(yong)于(yu)(yu)大于(yu)(yu)DN600的(de)(de)管(guan)道系統。8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)(ban)(ban)和墊(dian)(dian)環(huan)的(de)(de)有關標準，可(ke)參見HG/T 21547《管(guan)道用(yong)(yong)(yong)鋼制插(cha)板(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)、8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)》、ASME B16.48 Steel Line Blanks（8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)）、API 590Steel Line Blanks（8字(zi)盲(mang)(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)）。


圖 17.jpg


  有配(pei)管(guan)(guan)設(she)計(ji)人(ren)常咨詢(xun)筆者8字(zi)盲(mang)(mang)(mang)板(ban)與插(cha)(cha)板(ban)墊(dian)環的(de)(de)口徑分界(jie)問題。不同的(de)(de)設(she)計(ji)單位分界(jie)口徑和壓力等級可(ke)能不相同，8字(zi)盲(mang)(mang)(mang)板(ban)和插(cha)(cha)板(ban)墊(dian)環在本(ben)質上(shang)沒有什(shen)么(me)區(qu)別，區(qu)別就是當管(guan)(guan)徑比較(jiao)大、壓力等級高的(de)(de)情(qing)況(kuang)下(xia)，8字(zi)盲(mang)(mang)(mang)板(ban)的(de)(de)體積及重量(liang)比較(jiao)大，不方便拆卸，因此這時(shi)候通(tong)常使用(yong)(yong)(yong)插(cha)(cha)板(ban)墊(dian)環來代替。例(li)如對于Class 150的(de)(de)管(guan)(guan)道(dao)，DN300以下(xia)常用(yong)(yong)(yong)8字(zi)盲(mang)(mang)(mang)板(ban)，DN350以上(shang)常用(yong)(yong)(yong)插(cha)(cha)板(ban)墊(dian)環。具體見(jian)《工業管(guan)(guan)道(dao)配(pei)管(guan)(guan)設(she)計(ji)與工程(cheng)應用(yong)(yong)(yong)》、《管(guan)(guan)道(dao)器材選用(yong)(yong)(yong)與工程(cheng)應用(yong)(yong)(yong)》的(de)(de)詳細講述。


  某DN600插(cha)板墊環(huan)：材料選用A516-70，厚(hou)度和等(deng)級選用Class150。端部選用RF（突面），標準選用ASME B16.48。