點擊次數:862 發布時間:2012-11-16
調節閥dejiegoujiaoweifuza,qineibubuwendingliudongshidianxingdefeidingchangfuzaneiliuwenti。tiaojiefadezhendonghezaoshengshishouhenduoyinsugongtongzuoyongerchanshengde,yingchongfenkaolvjixiezhendong、氣蝕振動和流體動力學振動給調節閥帶來的影響。可以采取合理設計閥門材質和結構、減小閥門前後壓差、多(duo)級(ji)減(jian)壓(ya)結(jie)構(gou)和(he)避(bi)免(mian)閥(fa)門(men)在(zai)小(xiao)開(kai)度(du)下(xia)工(gong)作(zuo)等(deng)減(jian)振(zhen)降(jiang)噪(zao)的(de)常(chang)用(yong)方(fang)法(fa)。另(ling)外(wai)調(tiao)節(jie)閥(fa)的(de)選(xuan)型(xing)也(ye)應(ying)留(liu)有(you)足(zu)夠(gou)的(de)安(an)全(quan)裕(yu)量(liang),以(yi)便(bian)實(shi)際(ji)工(gong)作(zuo)狀(zhuang)態(tai)改(gai)變(bian)後(hou)有(you)足(zu)夠(gou)強(qiang)的(de)工(gong)況(kuang)適(shi)應(ying)性(xing)。
1 概述
調節閥是流體機械(包括電力機械、化工機械、流體動力機械等)中控製通流能力的關鍵部件,其性能和安全性與整個裝置的工作性能、效率和可靠性密切相關。在煉油、石油化工和發電等工業生產過程中,經常出現調節閥的振動、噪(zao)聲(sheng)與(yu)閥(fa)杆(gan)轉(zhuan)動(dong)現(xian)象(xiang),甚(shen)至(zhi)由(you)於(yu)振(zhen)動(dong)導(dao)致(zhi)閥(fa)杆(gan)斷(duan)裂(lie)等(deng)事(shi)故(gu)也(ye)時(shi)有(you)發(fa)生(sheng),嚴(yan)重(zhong)影(ying)響(xiang)設(she)備(bei)的(de)安(an)全(quan)和(he)壽(shou)命(ming)以(yi)及(ji)操(cao)作(zuo)人(ren)員(yuan)的(de)身(shen)心(xin)健(jian)康(kang)。克(ke)服(fu)調(tiao)節(jie)閥(fa)振(zhen)動(dong)與(yu)噪(zao)聲(sheng),延(yan)長(chang)其(qi)使(shi)用(yong)壽(shou)命(ming)已(yi)經(jing)引(yin)起(qi)許(xu)多(duo)設(she)計(ji)製(zhi)造(zao)部(bu)門(men)和(he)研(yan)究(jiu)單(dan)位(wei)的(de)高(gao)度(du)關(guan)注(zhu)。
2 原因分析
調節閥的振動與噪聲根據其誘發因素不同,大致可分為機械振動、氣蝕振動和流體動力學振動等原因。
2.1 流體動力學振動
介質在閥內的節流過程也是其受摩擦、shouzuliheraodongdeguocheng。tuanliutitongguobuliangraoliutidetiaojiefashixingchengxuanwo,xuanwohuisuizheliutidejixuliudongdeweiliuertuoluo。zhezhongxuanwotuoluopinlvdexingchengjiyingxiangyinsushifenfuza,bingyouhendadesuijixing,dingliangjisuanshifenkunnan,erkeguanquecunzaiyigezhudaotuoluopinlv。dangzheyizhudaotuoluopinlv(亦包括高次諧波)在zai與yu調tiao節jie閥fa及ji其qi附fu屬shu裝zhuang置zhi的de結jie構gou頻pin率lv接jie近jin或huo一yi致zhi時shi,發fa生sheng了le共gong振zhen,調tiao節jie閥fa就jiu產chan生sheng了le振zhen動dong,並bing伴ban隨sui著zhe噪zao聲sheng。振zhen動dong的de強qiang弱ruo隨sui主zhu導dao脫tuo落luo頻pin率lv的de強qiang弱ruo和he高gao次ci諧xie波bo波bo動dong方fang向xiang一yi致zhi性xing的de程cheng度du而er定ding。
2.2 機械振動
jixiezhendonggenjuqibiaoxianxingshikeyifenweiliangzhongzhuangtai。yizhongzhuangtaishitiaojiefadezhengtizhendong,jizhenggetiaojiefazaiguandaohuojizuoshangpinfanchandong,qiyuanyinshiyouyuguandaohuojizuojuliezhendong,yinqizhenggetiaojiefazhendong。ciwaihaiyupinlvyouguan,jidangwaibudepinlvyuxitongdeguyoupinlvxiangdenghuojiejinshishoupozhendongdenengliangdadaozuidazhi、產生共振。另一種狀態是調節閥閥瓣的振動,其原因主要是由於介質流速的急劇增加,使調節閥前後差壓急劇變化,引起整個
調節閥產生嚴重振蕩。
2.3 氣蝕振動
氣qi蝕shi振zhen動dong大da多duo發fa生sheng在zai液ye態tai介jie質zhi的de調tiao節jie閥fa內nei。氣qi蝕shi產chan生sheng的de根gen本ben原yuan因yin在zai於yu調tiao節jie閥fa內nei流liu體ti縮suo流liu加jia速su和he靜jing壓ya下xia降jiang引yin起qi液ye體ti汽qi化hua。調tiao節jie閥fa開kai度du越yue小xiao,其qi前qian後hou的de壓ya差cha越yue大da,流liu體ti加jia速su並bing產chan生sheng氣qi蝕shi的de可ke能neng性xing就jiu越yue大da,與yu之zhi對dui應ying的de阻zu塞sai流liu壓ya降jiang也ye就jiu越yue小xiao。
3 防範措施
從調節閥的(de)使(shi)用(yong)和(he)理(li)論(lun)分(fen)析(xi)可(ke)以(yi)證(zheng)明(ming),誘(you)發(fa)調(tiao)節(jie)閥(fa)振(zhen)動(dong)和(he)噪(zao)聲(sheng)的(de)因(yin)素(su)有(you)很(hen)多(duo),這(zhe)些(xie)因(yin)素(su)又(you)相(xiang)互(hu)影(ying)響(xiang),很(hen)多(duo)都(dou)是(shi)同(tong)時(shi)發(fa)生(sheng)的(de),這(zhe)就(jiu)使(shi)調(tiao)節(jie)閥(fa)的(de)減(jian)震(zhen)降(jiang)噪(zao)更(geng)加(jia)困(kun)難(nan),需(xu)要(yao)結(jie)合(he)閥(fa)門(men)材(cai)質(zhi)、結構和流體動力學等方麵綜合考慮。
3.1 預防機械振動
(1)調節閥安裝位置應遠離振動源,如不可避免,應采取預防措施。
(2)正zheng確que選xuan擇ze零ling部bu件jian。如ru果guo閥fa瓣ban快kuai速su的de忽hu高gao忽hu低di的de變bian化hua,閥fa門men定ding位wei器qi靈ling敏min度du又you太tai高gao,調tiao節jie器qi輸shu出chu微wei小xiao的de變bian化hua或huo飄piao移yi,就jiu會hui立li即ji轉zhuan換huan成cheng定ding位wei器qi輸shu出chu信xin號hao很hen大da,致zhi使shi閥fa振zhen蕩dang。調tiao節jie閥fa的de摩mo擦ca力li太tai小xiao,外wai界jie輸shu人ren信xin號hao有you微wei小xiao的de變bian化hua或huo飄piao移yi,會hui立li即ji傳chuan遞di給gei閥fa瓣ban,使shi其qi振zhen動dong。相xiang反fan,如ru調tiao節jie閥fa的de摩mo擦ca力li太tai大da,則ze在zai小xiao信xin號hao時shi動dong作zuo不bu了le,信xin號hao大da時shi一yi經jing動dong作zuo又you產chan生sheng過guo大da的de現xian象xiang,會hui使shi調tiao節jie閥fa產chan生sheng遲chi滯zhi性xing振zhen蕩dang。遇yu到dao這zhe種zhong情qing況kuang,應ying當dang減jian小xiao調tiao節jie閥fa相xiang應ying部bu分fen的de阻zu尼ni來lai解jie決jue,如ru更geng換huan填tian料liao等deng。
(3)合(he)理(li)設(she)計(ji)閥(fa)門(men)結(jie)構(gou)。為(wei)避(bi)免(mian)閥(fa)杆(gan)相(xiang)對(dui)於(yu)導(dao)向(xiang)套(tao)筒(tong)表(biao)麵(mian)的(de)側(ce)向(xiang)運(yun)動(dong),在(zai)高(gao)頻(pin)振(zhen)動(dong)下(xia)產(chan)生(sheng)疲(pi)勞(lao)斷(duan)裂(lie),提(ti)高(gao)閥(fa)門(men)的(de)抗(kang)振(zhen)能(neng)力(li),可(ke)將(jiang)容(rong)易(yi)承(cheng)受(shou)紊(wen)流(liu)形(xing)式(shi)的(de)柱(zhu)塞(sai)節(jie)流(liu)結(jie)構(gou)變(bian)為(wei)節(jie)流(liu)罩(zhao)節(jie)流(liu)結(jie)構(gou),將(jiang)懸(xuan)壁(bi)梁(liang)頂(ding)尖(jian)導(dao)向(xiang)方(fang)式(shi)改(gai)成(cheng)節(jie)流(liu)罩(zhao)導(dao)向(xiang)方(fang)式(shi),或(huo)采(cai)取(qu)縮(suo)小(xiao)導(dao)向(xiang)間(jian)隙(xi)、選用剛性導向和柱塞頭及加大閥杆直徑等方法。
3.2 預防氣蝕振動
(1)bimianxiaokaidugongzuo。tiaojiefakaidutaixiao,zhishijieliukouchuliusuzengda,yalixunsujianxiao,liutiliujingfamenhenrongyixingchengshanzhengheqishi。suoyiyingbimiantiaojiefachangshijianzaixiaokaiduxiagongzuo,tongshiyingjinliangjianxiaotiaojiefaqianhouyacha。
(2)helidekaichegongyi。shengchanxianchangdekaichegongyiduitiaojiefadeshiyongqingkuangzhiguanzhongyao,duiyugongzuoyalijiaogaoerqianhouyachajiaodidetiaojiefagengshiruci。zheshiyinweitiaojiefashigenjushejiyachajinxingxuanxingde,shinengbaozhengzaishejitiaojianxiadezhengchanganquanshiyong。danshishengchanxianchangdekaichegongyidaduodoushifamenguanbideqingkuangxia,shangyouguandaokaishijianya,dangfaqianyalidadaoshejiyaoqiushifamenkaiqi,ercishifahouyalirengranhenxiao,zhejiushifamenchuzaihenxiaodekaidu、很hen高gao的de壓ya差cha下xia的de工gong作zuo狀zhuang態tai,會hui產chan生sheng嚴yan重zhong的de振zhen蕩dang和he氣qi蝕shi,影ying響xiang閥fa門men的de使shi用yong壽shou命ming,更geng有you可ke能neng損sun壞huai閥fa門men。所suo以yi現xian場chang開kai車che時shi,應ying盡jin量liang使shi前qian後hou壓ya力li同tong時shi建jian立li到dao設she計ji條tiao件jian後hou,快kuai速su開kai啟qi閥fa門men,保bao證zheng閥fa門men在zai設she計ji條tiao件jian下xia工gong作zuo。
(3)duojifenpeiyajiang。tiaojiefaqianhouyachabuyingtaida,yinghelidexuanzefamendejiegouxingshijihelidejinxingyachafenpei,ruguotiaojianyunxukeyicaiyongduojijianya,bimianqishidefasheng。
(4)改進結構。若工況係統不宜於多級減壓結構,也可采用節流套筒的結構,但是套筒的結構和尺寸選擇也要根據實際情況(如介質中是否含有固體顆粒)合理選擇。
3.3 預防流體動力學振動
(1)baozhengzhixingjigoudeshuchuli。dangliutitongguotiaojiefashi,fabanzaijingyahedongyadezuoyongxiachanshengqiexianglihezhouxiangli。qiexianglishifabanzhuandong,zhouxianglishifabanyasuohuolashen。suoweitiaojiefadebupinghenglijiushizhiduizhixingchengdefabansuoshoudaodezhouxiangheli。bupinghenglizhijieyingxiangtiaojiefadexingchengweizhiyuzhixingjigouxinhaoyalizhijiandeguanxi。yinci,zhixingjigoudeshuchuliyingzuyikefubupinghengli,yibaozhengtiaojiezhiliang。
(2)改變流動狀態。為了防止高速汽流進人閥體後發生高速旋流,可在調節閥的閥體腔內加焊一塊擋汽板。
(3)避免產生共振。為克服流體誘發調節閥振動,應降低流體旋渦主導脫落頻率的形成概率和湍流體波動壓力場中各波動分量在方向、頻率等一致的概率。