塑料球閥墊片的密封原理
塑(su)料(liao)球(qiu)閥(fa)的(de)密(mi)封(feng)是(shi)兩(liang)個(ge)連(lian)接(jie)件(jian)中(zhong)間(jian)夾(jia)上(shang)墊(dian)片(pian)來(lai)實(shi)現(xian)密(mi)封(feng)的(de)。靜(jing)密(mi)封(feng)的(de)結(jie)構(gou)形(xing)式(shi)很(hen)多(duo),有(you)平(ping)麵(mian)墊(dian),梯(ti)形(xing)墊(dian),透(tou)鏡(jing)墊(dian)等(deng)。這(zhe)些(xie)塑(su)料(liao)球(qiu)閥(fa)墊(dian)片(pian)安(an)裝(zhuang)製(zhi)作(zuo)材(cai)料(liao)有(you)非(fei)金(jin)屬(shu)墊(dian)片(pian)、金屬墊片、符fu合he材cai料liao墊dian片pian三san大da種zhong類lei。為wei了le不bu同tong性xing質zhi的de介jie質zhi的de需xu要yao,墊dian片pian分fen為wei很hen多duo種zhong。墊dian片pian是shi解jie決jue靜jing密mi封feng處chu跑pao,冒mao,滴di,漏lou的de重zhong要yao零ling件jian。因yin此ci,墊dian片pian的de安an裝zhuang是shi一yi個ge很hen重zhong要yao的de環huan節jie。
一、 塑料球閥墊片密封處泄露種類
墊片密封泄漏有兩種,即界麵泄漏和滲透泄漏。
1、界jie麵mian泄xie漏lou是shi指zhi介jie質zhi從cong墊dian片pian表biao麵mian與yu連lian接jie件jian接jie觸chu的de密mi封feng麵mian之zhi間jian滲shen透tou出chu來lai的de一yi種zhong泄xie漏lou形xing式shi。界jie麵mian泄xie漏lou與yu靜jing密mi封feng麵mian的de形xing式shi,密mi封feng麵mian的de表biao麵mian粗cu糙cao度du,墊dian片pian的de材cai料liao性xing能neng及ji墊dian片pian安an裝zhuang質zhi量liang等deng因yin素su有you關guan。
2、滲(shen)透(tou)泄(xie)漏(lou)是(shi)指(zhi)介(jie)質(zhi)從(cong)墊(dian)片(pian)的(de)毛(mao)細(xi)孔(kong)中(zhong)滲(shen)透(tou)出(chu)來(lai)的(de)一(yi)種(zhong)泄(xie)漏(lou)形(xing)式(shi)。組(zu)織(zhi)疏(shu)鬆(song)的(de)植(zhi)物(wu)纖(xian)維(wei),動(dong)物(wu)纖(xian)維(wei),礦(kuang)物(wu)纖(xian)維(wei)材(cai)料(liao)製(zhi)作(zuo)的(de)墊(dian)片(pian)容(rong)易(yi)滲(shen)透(tou)泄(xie)漏(lou)。通(tong)常(chang)所(suo)說(shuo)的(de)阻(zu)止(zhi)滲(shen)透(tou),無(wu)泄(xie)漏(lou),隻(zhi)不(bu)過(guo)是(shi)滲(shen)透(tou)量(liang)非(fei)常(chang)微(wei)小(xiao)而(er)已(yi),肉(rou)眼(yan)基(ji)本(ben)是(shi)看(kan)不(bu)到(dao)滲(shen)漏(lou)的(de)。
3、塑料球閥的密封原理:是(shi)球(qiu)閥(fa)的(de)墊(dian)片(pian)的(de)密(mi)封(feng)原(yuan)理(li),當(dang)墊(dian)片(pian)在(zai)密(mi)封(feng)麵(mian)之(zhi)間(jian)未(wei)壓(ya)緊(jin)之(zhi)前(qian),墊(dian)片(pian)沒(mei)有(you)塑(su)性(xing)變(bian)形(xing)和(he)彈(dan)性(xing)變(bian)形(xing),介(jie)質(zhi)很(hen)容(rong)易(yi)從(cong)界(jie)麵(mian)泄(xie)漏(lou)。當(dang)墊(dian)片(pian)被(bei)壓(ya)緊(jin)以(yi)後(hou) ,墊(dian)片(pian)開(kai)始(shi)變(bian)形(xing),隨(sui)著(zhe)壓(ya)力(li)的(de)增(zeng)加(jia),墊(dian)片(pian)比(bi)壓(ya)增(zeng)大(da),墊(dian)片(pian)變(bian)形(xing)越(yue)大(da)。由(you)於(yu)墊(dian)片(pian)表(biao)麵(mian)層(ceng)變(bian)形(xing),墊(dian)片(pian)被(bei)擠(ji)進(jin)密(mi)封(feng)麵(mian)的(de)波(bo)穀(gu)中(zhong)去(qu),填(tian)滿(man)整(zheng)個(ge)波(bo)穀(gu),組(zu)織(zhi)介(jie)質(zhi)從(cong)界(jie)麵(mian)滲(shen)透(tou)出(chu)來(lai)。墊(dian)片(pian)中(zhong)間(jian)部(bu)分(fen)在(zai)壓(ya)緊(jin)力(li)的(de)作(zuo)用(yong)下(xia),除(chu)有(you)一(yi)定(ding)的(de)塑(su)性(xing)變(bian)形(xing)外(wai),還(hai)有(you)一(yi)定(ding)的(de)彈(dan)性(xing)變(bian)形(xing),兩(liang)密(mi)封(feng)麵(mian)在(zai)某(mou)些(xie)因(yin)素(su)的(de)作(zuo)用(yong)下(xia),間(jian)距(ju)變(bian)大(da)時(shi),墊(dian)片(pian)具(ju)有(you)回(hui)彈(dan)力(li),隨(sui)之(zhi)變(bian)厚(hou),填(tian)補(bu)密(mi)封(feng)麵(mian)間(jian)距(ju)的(de)變(bian)大(da),阻(zu)止(zhi)介(jie)質(zhi)從(cong)界(jie)麵(mian)泄(xie)漏(lou)。
4、影響塑料球閥dianpianxieloudeyinsushidianodeshentouxielouyujiezhideyali,shentounengli,dianocailiaodemaoxikongdaxiao,changduan,duidianpianshijiayalidedaxiaodengyinsuxiangguan。jiezhideyalidaerzhanduxiao,dianpiandemaoxikongdaerduan,zedianodeshentouliangda;反fan之zhi,則ze墊dian片pian的de滲shen透tou量liang小xiao。連lian接jie件jian中zhong的de墊dian片pian壓ya得de越yue緊jin,點dian哦o中zhong的de毛mao細xi孔kong也ye將jiang逐zhu漸jian縮suo小xiao,介jie質zhi從cong墊dian片pian中zhong的de滲shen透tou能neng力li件jian大da大da減jian小xiao,甚shen至zhi認ren為wei阻zu止zhi了le介jie質zhi的de滲shen透tou泄xie漏lou。給gei墊dian片pian施shi加jia適shi當dang的de緊jin力li不bu能neng過guo大da,否fou則ze會hui壓ya壞huai墊dian片pian,使shi墊dian片pian失shi去qu密mi封feng效xiao能neng。
二、螺栓施加的預緊力
螺luo栓shuan施shi加jia預yu緊jin力li的de確que定ding,是shi一yi個ge複fu雜za的de問wen題ti,它ta與yu密mi封feng形xing式shi,介jie質zhi壓ya力li,墊dian片pian材cai料liao,墊dian片pian尺chi寸cun,螺luo紋wen表biao麵mian粗cu糙cao度du,以yi及ji螺luo栓shuan螺luo母mu旋xuan轉zhuan有you無wu潤run滑hua等deng因yin素su相xiang關guan。有you潤run滑hua時shi,摩mo擦ca因yin數shu是shi0.1-.015,沒潤滑時,摩擦因數是2.2-3.0
螺栓施加預緊力的轉矩
A.原石油部在標準《安全墊片的技術要求》中規定的轉矩扳手,螺母直徑為M10~16的螺母旋緊力為150~300NM。guidingdexuanjinlijuweikaolvluoshuancaizhi,luowenjingduhebiaomiancucaodu,dianpiandexingshi,caizhijihoududengyinsu。tongshi,guidingzhuanjubanshoushiyongdefamenjifalanfanwei。
B.塑(su)料(liao)球(qiu)閥(fa)組(zu)裝(zhuang)時(shi)螺(luo)栓(shuan)螺(luo)母(mu)的(de)螺(luo)紋(wen)表(biao)麵(mian),以(yi)及(ji)相(xiang)應(ying)的(de)接(jie)觸(chu)麵(mian)應(ying)塗(tu)上(shang)潤(run)滑(hua)劑(ji)。經(jing)過(guo)長(chang)期(qi)使(shi)用(yong)後(hou)在(zai)擰(ning)緊(jin)時(shi),必(bi)須(xu)依(yi)據(ju)表(biao)麵(mian)狀(zhuang)況(kuang)的(de)變(bian)化(hua),重(zhong)新(xin)確(que)定(ding)預(yu)緊(jin)力(li)。
綜上所述,塑料球閥壓緊墊片的螺栓預緊力受多種因素的影響,一般來說,壓力高,溫度高比壓力低,溫度低時預緊力要大些;金屬墊片比非金屬墊片預緊力要大,介質粘度低,滲透力較強的比滲透力較弱的預緊力要大寫;墊片接觸麵積大的比墊片接觸麵積小的預緊力要大寫。總之,在保證試壓密封的條件下,根據具體情況盡量采用較小的螺栓預緊力。
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