盲(mang)(mang)板(ban)（Blind）、8字(zi)盲(mang)(mang)板(ban)（Spectacle Blind； Figure 8 Blind）、插板(ban)（Paddle Blank）以及墊環（Paddle Spacer），制造方(fang)法一般分(fen)三種(zhong)：鍛(duan)打、鑄(zhu)鍛(duan)、中(zhong)板(ban)割(ge)制。其中(zhong)鍛(duan)打產品(pin)價格(ge)最高，中(zhong)板(ban)次之(zhi)，鑄(zhu)鍛(duan)最低。而質量是鍛(duan)打和中(zhong)板(ban)的好，鑄(zhu)鍛(duan)的要稍差些。盲(mang)(mang)板(ban)或“8”字(zi)盲(mang)(mang)板(ban)與閥(fa)門(men)相比，其關斷作用更可靠而且更經濟。

  盲板、“8”字盲板、插板以(yi)及墊環(huan)都應有兩個和(he)匹配法(fa)蘭同(tong)樣的密(mi)封(feng)面(mian)(mian)。常用(yong)的密(mi)封(feng)面(mian)(mian)包含(han)平面(mian)(mian)、凹凸面(mian)(mian)、榫槽面(mian)(mian)和(he)環(huan)連面(mian)(mian)。

  盲(mang)板(ban)（見圖(tu)4-15）用(yong)于(yu)起隔離、切斷(duan)作用(yong)的(de)(de)(de)，和封頭、管帽所起的(de)(de)(de)作用(yong)是(shi)一(yi)樣的(de)(de)(de)。由于(yu)其密封性(xing)能好，對于(yu)需要(yao)完全隔離的(de)(de)(de)系統，一(yi)般都作為可靠(kao)的(de)(de)(de)隔離手(shou)段。盲(mang)板(ban)就是(shi)一(yi)個帶柄的(de)(de)(de)實心(xin)的(de)(de)(de)圓(yuan)，用(yong)于(yu)通常狀況下處于(yu)隔離狀態的(de)(de)(de)系統。盲(mang)板(ban)的(de)(de)(de)有關標準，可參見HG/T 20592～20635《鋼制(zhi)管法(fa)(fa)(fa)蘭(lan)、墊片、緊固件(jian)》和ASME B16.5《管法(fa)(fa)(fa)蘭(lan)和法(fa)(fa)(fa)蘭(lan)管件(jian)》。

  8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)（見圖(tu)4-16），形狀(zhuang)像“8”字，一端是(shi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)，另一端是(shi)節流(liu)環(huan)（墊(dian)(dian)(dian)(dian)(dian)環(huan)），但直(zhi)徑與管道的(de)管徑相同，并不起節流(liu)作(zuo)用(yong)(yong)(yong)。8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)，使用(yong)(yong)(yong)方便，需(xu)要(yao)(yao)隔(ge)離時，使用(yong)(yong)(yong)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)端，需(xu)要(yao)(yao)正(zheng)常操(cao)作(zuo)時，使用(yong)(yong)(yong)節流(liu)環(huan)（墊(dian)(dian)(dian)(dian)(dian)環(huan)）端，同時也可(ke)用(yong)(yong)(yong)于填補管路上盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)的(de)安(an)裝間隙。另一個(ge)特點就是(shi)標識明顯(xian)，易(yi)于辨認安(an)裝狀(zhuang)態。主(zhu)要(yao)(yao)用(yong)(yong)(yong)于小于等于DN600的(de)管道系統。插(cha)板(ban)(ban)(ban)（見圖(tu)4-17）和(he)墊(dian)(dian)(dian)(dian)(dian)環(huan)（見圖(tu)4-18）互為盲(mang)(mang)(mang)(mang)通，和(he)8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)的(de)作(zuo)用(yong)(yong)(yong)類似，主(zhu)要(yao)(yao)用(yong)(yong)(yong)于大于DN600的(de)管道系統。8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)和(he)墊(dian)(dian)(dian)(dian)(dian)環(huan)的(de)有關標準，可(ke)參見HG/T 21547《管道用(yong)(yong)(yong)鋼制插(cha)板(ban)(ban)(ban)、墊(dian)(dian)(dian)(dian)(dian)環(huan)、8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)》、ASME B16.48 Steel Line Blanks（8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)、墊(dian)(dian)(dian)(dian)(dian)環(huan)）、API 590Steel Line Blanks（8字盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)、墊(dian)(dian)(dian)(dian)(dian)環(huan)）。

  有配(pei)管(guan)設(she)計人(ren)常(chang)咨詢筆者(zhe)8字(zi)(zi)盲(mang)板(ban)(ban)與(yu)插(cha)(cha)板(ban)(ban)墊環(huan)(huan)的(de)口徑分界(jie)問(wen)題。不同的(de)設(she)計單(dan)位分界(jie)口徑和壓力(li)等(deng)級(ji)(ji)可能不相(xiang)同，8字(zi)(zi)盲(mang)板(ban)(ban)和插(cha)(cha)板(ban)(ban)墊環(huan)(huan)在(zai)本(ben)質上沒(mei)有什么區別，區別就(jiu)是當管(guan)徑比較(jiao)(jiao)大、壓力(li)等(deng)級(ji)(ji)高(gao)的(de)情(qing)況下，8字(zi)(zi)盲(mang)板(ban)(ban)的(de)體積(ji)及(ji)重量比較(jiao)(jiao)大，不方便拆卸，因(yin)此這時候通常(chang)使用(yong)插(cha)(cha)板(ban)(ban)墊環(huan)(huan)來代替。例如對于(yu)Class 150的(de)管(guan)道，DN300以(yi)下常(chang)用(yong)8字(zi)(zi)盲(mang)板(ban)(ban)，DN350以(yi)上常(chang)用(yong)插(cha)(cha)板(ban)(ban)墊環(huan)(huan)。具體見《工(gong)業管(guan)道配(pei)管(guan)設(she)計與(yu)工(gong)程應用(yong)》、《管(guan)道器材選用(yong)與(yu)工(gong)程應用(yong)》的(de)詳細講(jiang)述。

  某DN600插板墊環：材料選用(yong)A516-70，厚度(du)和等級選用(yong)Class150。端部選用(yong)RF（突面），標(biao)準選用(yong)ASME B16.48。