盲(mang)(mang)板（Blind）、8字(zi)盲(mang)(mang)板（Spectacle Blind； Figure 8 Blind）、插板（Paddle Blank）以(yi)及(ji)墊環（Paddle Spacer），制造方法一般分三種：鍛(duan)(duan)(duan)打、鑄(zhu)鍛(duan)(duan)(duan)、中(zhong)板割制。其(qi)中(zhong)鍛(duan)(duan)(duan)打產品價格最高，中(zhong)板次之，鑄(zhu)鍛(duan)(duan)(duan)最低(di)。而(er)質量是(shi)鍛(duan)(duan)(duan)打和(he)中(zhong)板的好，鑄(zhu)鍛(duan)(duan)(duan)的要稍差些(xie)。盲(mang)(mang)板或“8”字(zi)盲(mang)(mang)板與閥門相比(bi)，其(qi)關斷(duan)作用更可(ke)靠而(er)且更經濟。

  盲板、“8”字盲板、插板以及(ji)墊環(huan)都應有兩個和(he)(he)匹配法蘭同(tong)樣的密(mi)封面(mian)(mian)(mian)。常用的密(mi)封面(mian)(mian)(mian)包含平面(mian)(mian)(mian)、凹凸面(mian)(mian)(mian)、榫槽(cao)面(mian)(mian)(mian)和(he)(he)環(huan)連面(mian)(mian)(mian)。

  盲板（見圖(tu)4-15）用于起(qi)隔離(li)(li)(li)、切(qie)斷作用的(de)，和封頭、管(guan)(guan)帽所(suo)起(qi)的(de)作用是一(yi)樣的(de)。由于其密封性能好，對(dui)于需要完全隔離(li)(li)(li)的(de)系統，一(yi)般都作為(wei)可靠的(de)隔離(li)(li)(li)手段。盲板就是一(yi)個帶柄的(de)實心(xin)的(de)圓，用于通常(chang)狀(zhuang)況(kuang)下處于隔離(li)(li)(li)狀(zhuang)態的(de)系統。盲板的(de)有關標準，可參見HG/T 20592～20635《鋼制管(guan)(guan)法(fa)蘭、墊片、緊(jin)固件》和ASME B16.5《管(guan)(guan)法(fa)蘭和法(fa)蘭管(guan)(guan)件》。

  8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)（見(jian)圖(tu)4-16），形狀(zhuang)(zhuang)像“8”字(zi)(zi)，一端(duan)(duan)是盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)，另一端(duan)(duan)是節(jie)流環(huan)(huan)(huan)（墊(dian)(dian)環(huan)(huan)(huan)），但直徑與(yu)管(guan)道(dao)的(de)(de)管(guan)徑相同，并不起節(jie)流作用(yong)。8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)，使(shi)用(yong)方便，需(xu)要隔離時(shi)(shi)(shi)，使(shi)用(yong)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)端(duan)(duan)，需(xu)要正常操作時(shi)(shi)(shi)，使(shi)用(yong)節(jie)流環(huan)(huan)(huan)（墊(dian)(dian)環(huan)(huan)(huan)）端(duan)(duan)，同時(shi)(shi)(shi)也可(ke)(ke)用(yong)于填補(bu)管(guan)路(lu)上(shang)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)的(de)(de)安(an)裝間隙。另一個特點(dian)就是標(biao)識明顯，易(yi)于辨(bian)認安(an)裝狀(zhuang)(zhuang)態。主要用(yong)于小于等(deng)于DN600的(de)(de)管(guan)道(dao)系(xi)統。插板(ban)(ban)(ban)(ban)(ban)(ban)(ban)（見(jian)圖(tu)4-17）和(he)墊(dian)(dian)環(huan)(huan)(huan)（見(jian)圖(tu)4-18）互為盲(mang)(mang)(mang)(mang)通，和(he)8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)的(de)(de)作用(yong)類似，主要用(yong)于大于DN600的(de)(de)管(guan)道(dao)系(xi)統。8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)(ban)(ban)和(he)墊(dian)(dian)環(huan)(huan)(huan)的(de)(de)有(you)關標(biao)準，可(ke)(ke)參見(jian)HG/T 21547《管(guan)道(dao)用(yong)鋼制插板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)(huan)(huan)、8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)》、ASME B16.48 Steel Line Blanks（8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)(huan)(huan)）、API 590Steel Line Blanks（8字(zi)(zi)盲(mang)(mang)(mang)(mang)板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、插板(ban)(ban)(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)(huan)(huan)）。

  有(you)配(pei)管(guan)設計人常(chang)咨詢筆者8字盲板(ban)(ban)與(yu)插(cha)板(ban)(ban)墊(dian)(dian)環的(de)(de)口(kou)徑分(fen)界問題(ti)。不同(tong)的(de)(de)設計單(dan)位分(fen)界口(kou)徑和壓力(li)等(deng)級(ji)可能不相同(tong)，8字盲板(ban)(ban)和插(cha)板(ban)(ban)墊(dian)(dian)環在本質上(shang)沒有(you)什(shen)么區別(bie)，區別(bie)就是當(dang)管(guan)徑比較大(da)、壓力(li)等(deng)級(ji)高(gao)的(de)(de)情(qing)況下，8字盲板(ban)(ban)的(de)(de)體(ti)積及重量比較大(da)，不方便拆卸，因此這時候通常(chang)使用(yong)插(cha)板(ban)(ban)墊(dian)(dian)環來代(dai)替。例(li)如對于Class 150的(de)(de)管(guan)道(dao)，DN300以下常(chang)用(yong)8字盲板(ban)(ban)，DN350以上(shang)常(chang)用(yong)插(cha)板(ban)(ban)墊(dian)(dian)環。具體(ti)見《工業管(guan)道(dao)配(pei)管(guan)設計與(yu)工程(cheng)應用(yong)》、《管(guan)道(dao)器材選(xuan)用(yong)與(yu)工程(cheng)應用(yong)》的(de)(de)詳細講(jiang)述。

  某DN600插板墊環：材料選(xuan)用(yong)A516-70，厚度和等級選(xuan)用(yong)Class150。端部(bu)選(xuan)用(yong)RF（突面），標準選(xuan)用(yong)ASME B16.48。