一、爆破片概述
爆(bao)破(po)(po)片(pian)的作用(yong)是(shi)在設(she)備(bei)(bei)或(huo)管(guan)道(dao)壓(ya)力突然升高(gao)尚(shang)未引(yin)起(qi)爆(bao)炸前(qian),由于爆(bao)破(po)(po)片(pian)兩側壓(ya)力差達到預定溫(wen)(wen)度下的預定值時,即先(xian)行破(po)(po)裂,排(pai)出設(she)備(bei)(bei)或(huo)管(guan)道(dao)內的高(gao)壓(ya)介質。因此爆(bao)破(po)(po)片(pian)是(shi)防(fang)止設(she)備(bei)(bei)或(huo)管(guan)道(dao)破(po)(po)裂的一(yi)種安全泄(xie)(xie)放裝置。爆(bao)破(po)(po)片(pian)安全裝置具有結構簡(jian)單(dan)、靈敏、準確、無泄(xie)(xie)漏、泄(xie)(xie)放能力強等優(you)點。能夠在黏稠、高(gao)溫(wen)(wen)、低溫(wen)(wen)、腐蝕的環(huan)境下可靠地工作,還是(shi)超(chao)高(gao)壓(ya)容(rong)器(qi)的理想安全裝置。
爆破片典型圖見圖6.3.24。
二、爆破片的分類(lei)
按(an)照(zhao)結構型(xing)(xing)(xing)(xing)式來分類,爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)主要(yao)有(you)三種,即平板(ban)(ban)型(xing)(xing)(xing)(xing)、正(zheng)(zheng)(zheng)拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)和反拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)。平板(ban)(ban)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)的(de)(de)(de)(de)(de)綜合(he)性能(neng)(neng)較(jiao)差,主要(yao)用(yong)于(yu)低(di)壓(ya)(ya)(ya)(ya)和超低(di)壓(ya)(ya)(ya)(ya)工況,尤其(qi)(qi)是(shi)大型(xing)(xing)(xing)(xing)料倉。正(zheng)(zheng)(zheng)拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)和反拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)的(de)(de)(de)(de)(de)應用(yong)場合(he)較(jiao)多(duo)。對于(yu)傳統的(de)(de)(de)(de)(de)正(zheng)(zheng)(zheng)拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian),其(qi)(qi)工作(zuo)(zuo)原理是(shi)利(li)用(yong)材(cai)料的(de)(de)(de)(de)(de)拉(la)伸強(qiang)度(du)來控制爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)壓(ya)(ya)(ya)(ya)力(li),爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)的(de)(de)(de)(de)(de)拱(gong)(gong)(gong)出方(fang)向(xiang)與壓(ya)(ya)(ya)(ya)力(li)作(zuo)(zuo)用(yong)方(fang)向(xiang)一致(zhi)。在使(shi)用(yong)中(zhong)發現,所有(you)的(de)(de)(de)(de)(de)正(zheng)(zheng)(zheng)拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)都存在相同的(de)(de)(de)(de)(de)局限:爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)時,爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)碎片(pian)(pian)(pian)會進入泄放管道;由于(yu)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)的(de)(de)(de)(de)(de)中(zhong)心厚度(du)被(bei)有(you)意減弱,易于(yu)因疲(pi)勞而提前爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po);操(cao)(cao)作(zuo)(zuo)壓(ya)(ya)(ya)(ya)力(li)不能(neng)(neng)超過爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)最小爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)壓(ya)(ya)(ya)(ya)力(li)的(de)(de)(de)(de)(de)65%,由此(ci)導致(zhi)了反拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)的(de)(de)(de)(de)(de)出現。這(zhe)種爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)利(li)用(yong)材(cai)料的(de)(de)(de)(de)(de)抗(kang)壓(ya)(ya)(ya)(ya)強(qiang)度(du)來控制其(qi)(qi)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)壓(ya)(ya)(ya)(ya)力(li),較(jiao)之(zhi)傳統的(de)(de)(de)(de)(de)正(zheng)(zheng)(zheng)拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian),其(qi)(qi)具有(you)抗(kang)疲(pi)勞性能(neng)(neng)優良、爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)時不產生碎片(pian)(pian)(pian)且(qie)操(cao)(cao)作(zuo)(zuo)壓(ya)(ya)(ya)(ya)力(li)可達其(qi)(qi)最小爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)壓(ya)(ya)(ya)(ya)力(li)90%以上的(de)(de)(de)(de)(de)優點。細分之(zhi)下(xia),反拱(gong)(gong)(gong)型(xing)(xing)(xing)(xing)爆(bao)(bao)(bao)(bao)(bao)破(po)(po)(po)片(pian)(pian)(pian)包括反拱(gong)(gong)(gong)刻槽型(xing)(xing)(xing)(xing)、反拱(gong)(gong)(gong)腭齒型(xing)(xing)(xing)(xing)以及反拱(gong)(gong)(gong)刀架型(xing)(xing)(xing)(xing)等。
三、爆破(po)片的特點
爆破片與(yu)安(an)全閥比較(jiao),具(ju)有(you)結構簡(jian)單(dan)、靈敏、可靠、經濟、無泄(xie)漏、適用性(xing)強等優越性(xing),但也有(you)其局限性(xing),其特(te)點如下:
(1)密封性能好,在設備正常(chang)工(gong)作壓(ya)力下能保(bao)持嚴(yan)密不漏(lou)。
(2)泄壓反(fan)應迅速,爆破片的(de)動(dong)作一般在2~10ms內完成,而(er)安全閥則因為機(ji)械(xie)滯后(hou)作用,全部動(dong)作時間(jian)要高1~2個數量級。
(3)對黏稠性或粉末狀污物不敏感。即使(shi)氣體中含有一(yi)定量的污物也不致影響它的正常動(dong)作,不像安(an)全閥(fa)那(nei)樣,容易黏結或堵塞。
(4)爆破(po)元件(膜片(pian))動作(zuo)后不(bu)能復位,不(bu)但(dan)設(she)備(bei)內介質全部流失,設(she)備(bei)也(ye)得(de)中止運行。
(5)動(dong)作壓力不太穩定(ding)(ding),爆(bao)破片的爆(bao)破壓力允許偏差一(yi)般都比(bi)安全(quan)閥(fa)的穩定(ding)(ding)壓力允許偏差大(da)一(yi)些。
(6)爆破片的(de)使用(yong)壽命較短,常因疲(pi)勞而早期失效。
四(si)、爆破片的適用場所
(1)獨立的壓力容器和/或(huo)壓力管道(dao)系統設(she)有安全閥、爆破片裝置或(huo)這二者的組合裝置。
(2)滿足下列(lie)情(qing)況之一應優先(xian)選用(yong)爆破片:
①. 壓(ya)力有可能(neng)迅速(su)上(shang)升(sheng)的;
②. 泄(xie)放介質含(han)有顆粒、易(yi)(yi)(yi)沉(chen)淀、易(yi)(yi)(yi)結晶、易(yi)(yi)(yi)聚合和(he)介質黏度較大(da);
③. 泄放介質(zhi)有強腐蝕性(xing),使用安全閥時其(qi)價值很(hen)高;
④. 工(gong)藝介(jie)質十分昂(ang)貴或有劇毒,在工(gong)作過(guo)程(cheng)中不允許有任何泄漏,應(ying)與(yu)安全閥(fa)串聯使用(yong);
⑤. 工作壓力很低或很高時,選用安全閥(fa)則其(qi)制造比較困難(nan);
⑥. 當(dang)使用溫度(du)較低而影響安全閥工作特(te)性時;
⑦. 需要較大(da)泄(xie)放(fang)面積。
(3)對于一次性使用的(de)管路系統(如開車吹掃的(de)管路放空系統),爆破片(pian)的(de)破裂(lie)不影響操作和生產的(de)場合(he),設置爆破片(pian)。
(4)為減少爆破片破裂后的(de)工藝介質(zhi)的(de)損失,可與安(an)全(quan)閥串聯使用。
(5)作為壓力容器(qi)的附加(jia)安全設施,可與安全閥并(bing)聯使用,例如(ru)爆破片僅用于火災(zai)情況下的超(chao)壓泄放(fang)。
(6)為(wei)增加異常工(gong)況(kuang)(如火災等)下的泄放(fang)面積,爆破片可并聯使用。
(7)爆破片不適用于經常超壓和溫(wen)度波動(dong)很大(da)的(de)場合。
五、爆破片選用程序
(1)確定被(bei)保護設備或壓(ya)力管(guan)道系統是否需(xu)要設置爆破片。
(2)根據工藝介(jie)質和操(cao)作條(tiao)件(jian)確定爆破(po)片的(de)形(xing)式及(ji)材料(liao)。
(3)根據被保(bao)護管道系統的最(zui)(zui)高壓(ya)力及(ji)選用(yong)的爆(bao)破片(pian)形式,按標準規(gui)范(fan)確定(ding)爆(bao)破片(pian)的最(zui)(zui)小標定(ding)爆(bao)破壓(ya)力,設計(ji)爆(bao)破壓(ya)力。
(4)根據工藝條件、物理(li)參數計(ji)算(suan)爆(bao)破片(pian)的(de)安(an)全泄放量,選(xuan)定爆(bao)破片(pian)的(de)泄放面積和泄放口徑(jing)。
(5)填寫爆破(po)片裝置規格(ge)書,提供給材料采(cai)購專業(ye),作為訂貨的技術(shu)條(tiao)件(jian)。
六、爆破片有關標準規(gui)范
HG/T 20570.3《工(gong)(gong)藝系(xi)統工(gong)(gong)程設(she)計技術規定--爆破片的(de)設(she)置和選用》
GB 567《爆破片與(yu)爆破片裝置(zhi)》
GB 12353《拱型金屬爆(bao)破片裝(zhuang)置分類與(yu)安(an)裝(zhuang)尺寸》
GB/T 14566《正拱(gong)形(xing)金屬爆破片型式與參數》
GB/T 14567《反拱形金屬爆破片型(xing)式(shi)與參數(shu)》
GB/T 14568《開縫形金屬爆破片型式與參(can)數》
GB/T 16181《爆破片裝置夾持器型式和(he)外形尺寸》
七(qi)、安全閥與爆破片(pian)性能比(bi)較
安全閥(fa)與爆破片性(xing)能比較見表6.3.13。