盲(mang)板（Blind）、8字盲(mang)板（Spectacle Blind； Figure 8 Blind）、插(cha)板（Paddle Blank）以(yi)及(ji)墊環（Paddle Spacer），制(zhi)造方法一般分三種：鍛(duan)打、鑄鍛(duan)、中(zhong)板割制(zhi)。其中(zhong)鍛(duan)打產品價格(ge)最高(gao)，中(zhong)板次之(zhi)，鑄鍛(duan)最低。而(er)質量(liang)是鍛(duan)打和中(zhong)板的好(hao)，鑄鍛(duan)的要(yao)稍差些。盲(mang)板或“8”字盲(mang)板與(yu)閥門相比，其關斷(duan)作(zuo)用更可靠(kao)而(er)且更經濟(ji)。


  盲(mang)板(ban)、“8”字(zi)盲(mang)板(ban)、插板(ban)以及墊(dian)環都應(ying)有兩(liang)個和(he)匹配(pei)法蘭同(tong)樣的(de)密(mi)封(feng)面(mian)(mian)(mian)。常用的(de)密(mi)封(feng)面(mian)(mian)(mian)包含平面(mian)(mian)(mian)、凹凸面(mian)(mian)(mian)、榫槽面(mian)(mian)(mian)和(he)環連面(mian)(mian)(mian)。


  盲(mang)板（見圖4-15）用于起隔(ge)離(li)、切斷作(zuo)(zuo)(zuo)用的(de)(de)，和(he)封頭、管(guan)(guan)(guan)帽所起的(de)(de)作(zuo)(zuo)(zuo)用是(shi)一(yi)樣(yang)的(de)(de)。由于其(qi)密封性能(neng)好，對于需要完全隔(ge)離(li)的(de)(de)系統，一(yi)般(ban)都作(zuo)(zuo)(zuo)為(wei)可靠的(de)(de)隔(ge)離(li)手段。盲(mang)板就是(shi)一(yi)個(ge)帶柄的(de)(de)實心的(de)(de)圓，用于通常狀況下處于隔(ge)離(li)狀態的(de)(de)系統。盲(mang)板的(de)(de)有關標準，可參見HG/T 20592～20635《鋼制管(guan)(guan)(guan)法蘭、墊片、緊固件》和(he)ASME B16.5《管(guan)(guan)(guan)法蘭和(he)法蘭管(guan)(guan)(guan)件》。


圖 15.jpg


  8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)（見(jian)圖(tu)4-16），形狀像“8”字(zi)，一(yi)端(duan)是(shi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，另(ling)一(yi)端(duan)是(shi)節流環（墊(dian)環），但(dan)直徑(jing)與管(guan)道(dao)(dao)的(de)(de)管(guan)徑(jing)相同，并不起節流作(zuo)用(yong)(yong)。8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，使(shi)用(yong)(yong)方便，需要隔離時，使(shi)用(yong)(yong)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)端(duan)，需要正常操作(zuo)時，使(shi)用(yong)(yong)節流環（墊(dian)環）端(duan)，同時也可用(yong)(yong)于(yu)(yu)(yu)填(tian)補管(guan)路上盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)(de)安裝間(jian)隙。另(ling)一(yi)個(ge)特點就是(shi)標識明顯，易于(yu)(yu)(yu)辨(bian)認安裝狀態。主要用(yong)(yong)于(yu)(yu)(yu)小于(yu)(yu)(yu)等于(yu)(yu)(yu)DN600的(de)(de)管(guan)道(dao)(dao)系(xi)統。插板(ban)(ban)(ban)(ban)(ban)（見(jian)圖(tu)4-17）和墊(dian)環（見(jian)圖(tu)4-18）互為盲(mang)(mang)(mang)通(tong)，和8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)(de)作(zuo)用(yong)(yong)類似，主要用(yong)(yong)于(yu)(yu)(yu)大于(yu)(yu)(yu)DN600的(de)(de)管(guan)道(dao)(dao)系(xi)統。8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)和墊(dian)環的(de)(de)有關標準，可參(can)見(jian)HG/T 21547《管(guan)道(dao)(dao)用(yong)(yong)鋼(gang)制插板(ban)(ban)(ban)(ban)(ban)、墊(dian)環、8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)》、ASME B16.48 Steel Line Blanks（8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)、墊(dian)環）、API 590Steel Line Blanks（8字(zi)盲(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)、墊(dian)環）。


圖 17.jpg


  有(you)配管設計人常咨詢筆(bi)者8字盲板(ban)(ban)與(yu)插(cha)板(ban)(ban)墊(dian)環(huan)的(de)口徑(jing)分(fen)界問(wen)題(ti)。不(bu)同的(de)設計單位分(fen)界口徑(jing)和壓力等級(ji)可能不(bu)相同，8字盲板(ban)(ban)和插(cha)板(ban)(ban)墊(dian)環(huan)在本質上沒有(you)什么區(qu)別，區(qu)別就是當管徑(jing)比(bi)較大、壓力等級(ji)高的(de)情況下(xia)，8字盲板(ban)(ban)的(de)體積及重量比(bi)較大，不(bu)方便拆卸，因此(ci)這時(shi)候通(tong)常使(shi)用(yong)(yong)插(cha)板(ban)(ban)墊(dian)環(huan)來代(dai)替。例如對(dui)于Class 150的(de)管道(dao)(dao)，DN300以下(xia)常用(yong)(yong)8字盲板(ban)(ban)，DN350以上常用(yong)(yong)插(cha)板(ban)(ban)墊(dian)環(huan)。具體見《工業管道(dao)(dao)配管設計與(yu)工程應用(yong)(yong)》、《管道(dao)(dao)器(qi)材選(xuan)用(yong)(yong)與(yu)工程應用(yong)(yong)》的(de)詳細講述。


  某DN600插板(ban)墊環：材料(liao)選(xuan)用A516-70，厚度(du)和等(deng)級選(xuan)用Class150。端部選(xuan)用RF（突(tu)面），標準選(xuan)用ASME B16.48。