盲(mang)板(ban)(ban)(ban)（Blind）、8字盲(mang)板(ban)(ban)(ban)（Spectacle Blind； Figure 8 Blind）、插板(ban)(ban)(ban)（Paddle Blank）以及(ji)墊環(huan)（Paddle Spacer），制造(zao)方(fang)法(fa)一般分(fen)三(san)種：鍛(duan)打(da)、鑄鍛(duan)、中(zhong)板(ban)(ban)(ban)割制。其中(zhong)鍛(duan)打(da)產品價格最高，中(zhong)板(ban)(ban)(ban)次(ci)之，鑄鍛(duan)最低。而質量是(shi)鍛(duan)打(da)和中(zhong)板(ban)(ban)(ban)的(de)好(hao)，鑄鍛(duan)的(de)要(yao)稍(shao)差些。盲(mang)板(ban)(ban)(ban)或“8”字盲(mang)板(ban)(ban)(ban)與(yu)閥門(men)相比(bi)，其關斷作用(yong)更可靠而且更經濟。
盲板、“8”字盲板、插(cha)板以及(ji)墊環(huan)都應(ying)有兩(liang)個和(he)匹(pi)配法蘭同樣的密(mi)封面(mian)。常用的密(mi)封面(mian)包(bao)含平面(mian)、凹(ao)凸(tu)面(mian)、榫槽面(mian)和(he)環(huan)連面(mian)。
盲板（見圖4-15）用(yong)于(yu)(yu)(yu)起(qi)隔(ge)離、切斷作(zuo)(zuo)用(yong)的(de)，和(he)封頭、管(guan)帽所起(qi)的(de)作(zuo)(zuo)用(yong)是一(yi)(yi)樣的(de)。由(you)于(yu)(yu)(yu)其密封性能好，對于(yu)(yu)(yu)需要完全隔(ge)離的(de)系統，一(yi)(yi)般都作(zuo)(zuo)為(wei)可靠(kao)的(de)隔(ge)離手段。盲板就是一(yi)(yi)個(ge)帶柄的(de)實(shi)心的(de)圓，用(yong)于(yu)(yu)(yu)通常(chang)狀況(kuang)下處于(yu)(yu)(yu)隔(ge)離狀態的(de)系統。盲板的(de)有關(guan)標準(zhun)，可參(can)見HG/T 20592～20635《鋼制(zhi)管(guan)法蘭、墊片、緊固件》和(he)ASME B16.5《管(guan)法蘭和(he)法蘭管(guan)件》。
8字(zi)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)（見圖(tu)4-16），形狀像“8”字(zi)(zi)(zi)，一(yi)端(duan)(duan)是(shi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，另(ling)一(yi)端(duan)(duan)是(shi)節(jie)(jie)流(liu)環(huan)（墊(dian)(dian)環(huan)），但直徑與管道(dao)的(de)管徑相同，并(bing)不起節(jie)(jie)流(liu)作用(yong)。8字(zi)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)，使用(yong)方便(bian)，需要隔離時，使用(yong)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)端(duan)(duan)，需要正常(chang)操作時，使用(yong)節(jie)(jie)流(liu)環(huan)（墊(dian)(dian)環(huan)）端(duan)(duan)，同時也可用(yong)于(yu)填補管路(lu)上盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)安裝間隙。另(ling)一(yi)個特(te)點(dian)就是(shi)標識明顯，易于(yu)辨認安裝狀態。主要用(yong)于(yu)小(xiao)于(yu)等于(yu)DN600的(de)管道(dao)系統。插(cha)板(ban)(ban)(ban)(ban)(ban)（見圖(tu)4-17）和(he)墊(dian)(dian)環(huan)（見圖(tu)4-18）互為盲(mang)(mang)通，和(he)8字(zi)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)的(de)作用(yong)類似，主要用(yong)于(yu)大于(yu)DN600的(de)管道(dao)系統。8字(zi)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)(ban)(ban)和(he)墊(dian)(dian)環(huan)的(de)有(you)關標準，可參見HG/T 21547《管道(dao)用(yong)鋼制插(cha)板(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)、8字(zi)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)》、ASME B16.48 Steel Line Blanks（8字(zi)(zi)(zi)盲(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)(zi)(zi)盲(mang)(mang)板(ban)(ban)(ban)(ban)(ban)、插(cha)板(ban)(ban)(ban)(ban)(ban)、墊(dian)(dian)環(huan)）。
有配管設(she)計(ji)(ji)人常咨詢筆(bi)者(zhe)8字(zi)盲板(ban)(ban)與(yu)插板(ban)(ban)墊環的(de)(de)口徑(jing)分界問題。不(bu)同的(de)(de)設(she)計(ji)(ji)單(dan)位分界口徑(jing)和(he)壓(ya)力等(deng)級(ji)可能不(bu)相同，8字(zi)盲板(ban)(ban)和(he)插板(ban)(ban)墊環在本質上(shang)沒(mei)有什么(me)區別，區別就(jiu)是當管徑(jing)比(bi)較(jiao)大(da)、壓(ya)力等(deng)級(ji)高的(de)(de)情況下，8字(zi)盲板(ban)(ban)的(de)(de)體積及重量(liang)比(bi)較(jiao)大(da)，不(bu)方便(bian)拆卸，因(yin)此這時候(hou)通常使(shi)用(yong)插板(ban)(ban)墊環來代(dai)替。例如(ru)對于Class 150的(de)(de)管道(dao)，DN300以下常用(yong)8字(zi)盲板(ban)(ban)，DN350以上(shang)常用(yong)插板(ban)(ban)墊環。具體見《工(gong)(gong)業管道(dao)配管設(she)計(ji)(ji)與(yu)工(gong)(gong)程(cheng)應用(yong)》、《管道(dao)器材選用(yong)與(yu)工(gong)(gong)程(cheng)應用(yong)》的(de)(de)詳細講述(shu)。
某DN600插板墊環(huan)：材料(liao)選(xuan)用A516-70，厚度和等級選(xuan)用Class150。端部選(xuan)用RF（突面），標準選(xuan)用ASME B16.48。
