FESTO電磁閥閥門應考慮的(de)問題(ti)資料有(you)哪些(xie)?
FESTO電(dian)磁閥的(de)(de)(de)控制(zhi)要求(qiu)也越來越高(gao),越來越復雜。所(suo)以(yi)電(dian)動閥門在電(dian)氣(qi)控制(zhi)方(fang) 面的(de)(de)(de)設(she)計(ji)也在不斷更新(xin)。隨著科學技術的(de)(de)(de)進步(bu)及(ji)計(ji)算機的(de)(de)(de)普及(ji)應用(yong),新(xin)型的(de)(de)(de)、多樣的(de)(de)(de)電(dian)氣(qi)控制(zhi)方(fang)式(shi)將(jiang)不斷地出現。對(dui)電(dian)動閥門總(zong)體控制(zhi)方(fang)面的(de)(de)(de)考(kao)慮,應注(zhu)意選擇FESTO電(dian)磁閥的(de)(de)(de)控制(zhi)方(fang)式(shi)。
例如,根據工程需(xu)要(yao),是(shi)否使(shi)用集中(zhong)控(kong)制(zhi)方式,還是(shi)單臺控(kong)制(zhi)方式,是(shi)否與其他設備聯動,程序控(kong)制(zhi)還是(shi)應(ying)用計(ji)算機程序控(kong)制(zhi)等等,其控(kong)制(zhi)原理都(dou) 不樣。
FESTO電(dian)磁閥(fa)樣本(ben)給出的(de)(de)僅是(shi)標(biao)準電(dian)氣控(kong)(kong)制(zhi)(zhi)原理(li),因此使用部門(men)(men)(men)應(ying)與(yu)電(dian)動裝置廠進(jin)行(xing)(xing)技術交(jiao)底,明確技術要(yao)求(qiu)。 此外,在選擇電(dian)動閥(fa)門(men)(men)(men)時,應(ying)考慮是(shi)否附加購置電(dian)動閥(fa)門(men)(men)(men)控(kong)(kong)制(zhi)(zhi)器(qi)。因為般(ban)情(qing)況(kuang)(kuang),控(kong)(kong)制(zhi)(zhi)器(qi)是(shi)需(xu)要(yao)單獨購買(mai)的(de)(de)。多數情(qing)況(kuang)(kuang)下,采用單臺控(kong)(kong)制(zhi)(zhi)時,是(shi)需(xu)要(yao)購買(mai)控(kong)(kong)制(zhi)(zhi)器(qi)的(de)(de), 因為購買(mai)控(kong)(kong)制(zhi)(zhi)器(qi)比用戶自行(xing)(xing)設(she)計、制(zhi)(zhi)造要(yao)方便(bian)、便(bian)宜。當(dang)電(dian)氣控(kong)(kong)制(zhi)(zhi)滿足不(bu)了工程設(she)計要(yao)求(qiu)時,應(ying)向廠提出修(xiu)改(gai)或(huo)重(zhong)新設(she)計。
FESTO電磁閥(fa)實現(xian)閥(fa)門程控(kong)、自(zi)控(kong)和遙控(kong)*的(de)(de)設(she)備(bei),其運(yun)動過程可(ke)由行程、轉矩或軸向推力(li)的(de)(de)大小來控(kong)制。由于(yu)閥(fa)門電動裝(zhuang)置的(de)(de)工作(zuo)特性和利用率(lv)取決于(yu)閥(fa)門的(de)(de)種類、裝(zhuang)置工作(zuo)規(gui)范及閥(fa)門在管線或設(she)備(bei)上的(de)(de)位置,因此,正(zheng)確選擇閥(fa)門電動裝(zhuang)置,對(dui)防止(zhi)出(chu)現(xian)超負荷現(xian)象(工作(zuo)轉矩高于(yu)控(kong)制轉矩)關重要(yao)。通(tong)常,正(zheng)確選擇閥(fa)門電動裝(zhuang)置的(de)(de)依據如下(xia):
操作(zuo)力(li)矩(ju)操作(zuo)力(li)矩(ju)是(shi)選擇閥(fa)(fa)門(men)電動裝置的zui主要參數,電動裝置輸出力(li)矩(ju)應為閥(fa)(fa)門(men)操作(zuo)zui大力(li)矩(ju)的1.2~1.5倍。
操作推力(li)(li)(li)FESTO電(dian)磁(ci)閥(fa)(fa)閥(fa)(fa)門電(dian)動裝置的主機結構有兩種(zhong):種(zhong)是不配置推力(li)(li)(li)盤(pan),直接(jie)輸(shu)(shu)出(chu)(chu)(chu)力(li)(li)(li)矩;另種(zhong)是配置推力(li)(li)(li)盤(pan),輸(shu)(shu)出(chu)(chu)(chu)力(li)(li)(li)矩通(tong)過推力(li)(li)(li)盤(pan)中的閥(fa)(fa)桿螺(luo)母轉換為輸(shu)(shu)出(chu)(chu)(chu)推力(li)(li)(li)。
輸(shu)出軸(zhou)轉動(dong)(dong)圈數閥(fa)(fa)門(men)電動(dong)(dong)裝(zhuang)置(zhi)輸(shu)出軸(zhou)轉動(dong)(dong)圈數的多少(shao)與閥(fa)(fa)門(men)的公稱(cheng)通徑、閥(fa)(fa)桿(gan)螺(luo)距(ju)(ju)、螺(luo)紋頭數有關,要按M=H/ZS計算(M為(wei)電動(dong)(dong)裝(zhuang)置(zhi)應滿(man)足(zu)的總轉動(dong)(dong)圈數,H為(wei)閥(fa)(fa)門(men)開(kai)啟高度,S為(wei)閥(fa)(fa)桿(gan)傳動(dong)(dong)螺(luo)紋螺(luo)距(ju)(ju),Z為(wei)閥(fa)(fa)桿(gan)螺(luo)紋頭數)。
FESTO電磁(ci)閥(fa)(fa)閥(fa)(fa)桿(gan)直(zhi)徑(jing)(jing)對多回轉(zhuan)(zhuan)類明桿(gan)閥(fa)(fa)門,如果電動裝(zhuang)置允許通(tong)過(guo)的(de)(de)(de)zui大(da)(da)閥(fa)(fa)桿(gan)直(zhi)徑(jing)(jing)不能(neng)(neng)通(tong)過(guo)所配閥(fa)(fa)門的(de)(de)(de)閥(fa)(fa)桿(gan),便不能(neng)(neng)組裝(zhuang)成電動閥(fa)(fa)門。因此,電動裝(zhuang)置空心輸(shu)出軸的(de)(de)(de)內(nei)徑(jing)(jing)必須大(da)(da)于明桿(gan)閥(fa)(fa)門的(de)(de)(de)閥(fa)(fa)桿(gan)外徑(jing)(jing)。對部分(fen)回轉(zhuan)(zhuan)閥(fa)(fa)門以(yi)及多回轉(zhuan)(zhuan)閥(fa)(fa)門中(zhong)的(de)(de)(de)暗桿(gan)閥(fa)(fa)門,雖不用(yong)考慮(lv)閥(fa)(fa)桿(gan)直(zhi)徑(jing)(jing)的(de)(de)(de)通(tong)過(guo)問題,但在選配時(shi)亦應充分(fen)考慮(lv)閥(fa)(fa)桿(gan)直(zhi)徑(jing)(jing)與鍵槽的(de)(de)(de)尺(chi)寸,使組裝(zhuang)后能(neng)(neng)正常(chang)工作。
輸出轉速FESTO電磁閥閥門(men)的(de)啟閉速度(du)(du)若過快(kuai),易產生(sheng)水擊現象(xiang)。因此,應(ying)根據不同(tong)使用條件,選擇(ze)恰(qia)當的(de)啟閉速度(du)(du)。
FESTO電(dian)(dian)(dian)(dian)(dian)磁(ci)閥有其(qi)特殊要求,即必(bi)須能夠限定(ding)(ding)轉矩(ju)(ju)或軸向力。通常閥門(men)電(dian)(dian)(dian)(dian)(dian)動(dong)裝置采用限制(zhi)轉矩(ju)(ju)的(de)(de)連軸器。當電(dian)(dian)(dian)(dian)(dian)動(dong)裝置規格確(que)定(ding)(ding)之后,其(qi)控制(zhi)轉矩(ju)(ju)也(ye)就確(que)定(ding)(ding)了。般在預確(que)定(ding)(ding)的(de)(de)時間內運行,電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)不會超負荷。但如出(chu)現下列情況便可能導致(zhi)超負荷:FESTO電(dian)(dian)(dian)(dian)(dian)磁(ci)閥是(shi)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)壓低,得不到所(suo)需的(de)(de)轉矩(ju)(ju),使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)停止轉動(dong);二是(shi)錯誤地(di)調定(ding)(ding)轉矩(ju)(ju)限制(zhi)機(ji)(ji)構,使(shi)(shi)其(qi)大(da)于停止的(de)(de)轉矩(ju)(ju),造成連續(xu)產生(sheng)過大(da)轉矩(ju)(ju),使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)停止轉動(dong);三(san)是(shi)斷續(xu)使(shi)(shi)用,產生(sheng)的(de)(de)熱量(liang)(liang)積蓄,超過了電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)的(de)(de)允許溫升值;四是(shi)因(yin)某種(zhong)原因(yin)轉矩(ju)(ju)限制(zhi)機(ji)(ji)構電(dian)(dian)(dian)(dian)(dian)路(lu)發(fa)生(sheng)故障,使(shi)(shi)轉矩(ju)(ju)過大(da);五是(shi)使(shi)(shi)用環(huan)境(jing)溫度過高(gao),相對使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)熱容量(liang)(liang)下降。
FESTO電磁閥(fa)(fa)(fa)(fa)的(de)震蕩(dang)導(dao)致產(chan)量下(xia)(xia)降、次品(pin)率(lv)增加、能耗(hao)增加、效率(lv)降低。控(kong)(kong)制(zhi)回路(lu)中(zhong)*的(de)活(huo)動部分是控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)。如(ru)果控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)包(bao)含非線(xian)性,例如(ru):摩(mo)擦(ca)、后座力(li)和(he)死區,閥(fa)(fa)(fa)(fa)的(de)輸出可(ke)能震蕩(dang),這將導(dao)致過程輸出震蕩(dang)。在(zai)控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)的(de)許(xu)多種非線(xian)性中(zhong),摩(mo)擦(ca)是zui普(pu)遍也是長期存在(zai)的(de)問(wen)題(ti),它不僅降低了控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)的(de),同時也導(dao)致控(kong)(kong)制(zhi)回路(lu)的(de)下(xia)(xia)降。使用(yong)侵(qin)(qin)入(ru)式(shi)方法(fa)(控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)在(zai)非工(gong)作狀態下(xia)(xia),檢(jian)測(ce)并(bing)診斷(duan)其(qi)故障(1)),例如(ru)行程檢(jian)測(ce),可(ke)以很容易地(di)檢(jian)測(ce)摩(mo)擦(ca)。但將這種侵(qin)(qin)入(ru)式(shi)方法(fa)應用(yong)到(dao)整個工(gong)廠中(zhong)檢(jian)測(ce)工(gong)廠里幾(ji)百個或者更多的(de)控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)既費(fei)時費(fei)力(li),又(you)不可(ke)行。
盡管有很多侵(qin)入(ru)式方(fang)法(fa)(fa)能(neng)夠對FESTO電磁閥(fa)的(de)進行分析(2~5),但(dan)對非(fei)(fei)侵(qin)入(ru)式方(fang)法(fa)(fa)的(de)分析和研(yan)究很少在文獻中(zhong)(zhong)出(chu)現。Horch方(fang)法(fa)(fa)成功地(di)檢(jian)測(ce)出(chu)流量(liang)回路中(zhong)(zhong)的(de)摩擦(ca),但(dan)它不能(neng)應用(yong)到(dao)可壓(ya)縮流體上(6)。Ren2gaswamy提(ti)(ti)出(chu)的(de)方(fang)法(fa)(fa)依賴于數據的(de)時間趨勢,但(dan)這經常(chang)受(shou)(shou)到(dao)噪聲或(huo)干擾的(de)影響。數據的(de)趨勢曲線在很大程度上受(shou)(shou)過程和控制器動態的(de)影響(7)。Stenman提(ti)(ti)出(chu)了種(zhong)基于模型(xing)的(de)方(fang)法(fa)(fa)來檢(jian)測(ce)控制閥(fa)的(de)摩擦(ca)(8),這種(zhong)方(fang)法(fa)(fa)需要知道過程的(de)模型(xing)和大量(liang)的(de)整定參數,而從日常(chang)操作的(de)數據中(zhong)(zhong)獲取閉環回路模型(xing)是(shi)非(fei)(fei)常(chang)困難的(de)。
FESTO電磁閥(fa)種(zhong)基于數(shu)(shu)據(ju)的(de)(de)(de)非(fei)侵(qin)入(ru)(ru)式方法(fa)可以地減少維(wei)持控制所需的(de)(de)(de)費用(yong)(yong)。本文(wen)介紹了種(zhong)不基于數(shu)(shu)據(ju)模型的(de)(de)(de)非(fei)侵(qin)入(ru)(ru)式方法(fa),這(zhe)種(zhong)方法(fa)特點(dian)是(shi)不必對系統施加額(e)外的(de)(de)(de)激(ji)勵或進行試驗(yan),只要利用(yong)(yong)正常操作狀態下(xia)的(de)(de)(de)系統輸入(ru)(ru)輸出(chu)數(shu)(shu)據(ju)就(jiu)可以估計系統的(de)(de)(de)動態特性,所以應用(yong)(yong)上(shang)簡單易行,它的(de)(de)(de)這(zhe)些優(you)點(dian)使(shi)其成為控制系統檢測的(de)(de)(de)有(you)用(yong)(yong)工具。
FESTO電磁閥(fa)的(de)(de)(de)(de)(de)反(fan)饋(kui)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)回(hui)路(lu)。這個(ge)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)回(hui)路(lu)是(shi)(shi)通過調(diao)節被(bei)控(kong)(kong)(kong)變(bian)(bian)量使(shi)過程值達(da)到(dao)期望的(de)(de)(de)(de)(de)設定(ding)(ding)值。每個(ge)回(hui)路(lu)需(xu)要已知三個(ge)參數,即:設定(ding)(ding)值(SP),被(bei)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)變(bian)(bian)量值(PV),控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)器輸(shu)出值(OP)。在(zai)(zai)文獻(9,10)中,討論(lun)了評估控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)回(hui)路(lu)或(huo)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)器的(de)(de)(de)(de)(de)方(fang)法,例(li)如:zui小(xiao)誤差(cha)(cha)標準(zhun)和時間標準(zhun)。這里主要的(de)(de)(de)(de)(de)難(nan)點是(shi)(shi)如何(he)利用(yong)日常操作數據確(que)定(ding)(ding)導(dao)致控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)系統差(cha)(cha)的(de)(de)(de)(de)(de)根(gen)本原因。控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)回(hui)路(lu)差(cha)(cha)可(ke)能是(shi)(shi)由于(yu)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)器參數整(zheng)定(ding)(ding)不合理(li),擾(rao)動的(de)(de)(de)(de)(de)存(cun)(cun)在(zai)(zai)或(huo)者回(hui)路(lu)中存(cun)(cun)在(zai)(zai)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)引起的(de)(de)(de)(de)(de)。因為基于(yu)線(xian)(xian)(xian)性(xing)(xing)(xing)理(li)論(lun)的(de)(de)(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)器是(shi)(shi)在(zai)(zai)回(hui)路(lu)線(xian)(xian)(xian)性(xing)(xing)(xing)的(de)(de)(de)(de)(de)假設下設計(ji)的(de)(de)(de)(de)(de),如果(guo)應用(yong)到(dao)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)對象將導(dao)致變(bian)(bian)差(cha)(cha)。回(hui)路(lu)的(de)(de)(de)(de)(de)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)可(ke)能是(shi)(shi)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)閥(fa)存(cun)(cun)在(zai)(zai)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)或(huo)過程本身存(cun)(cun)在(zai)(zai)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)引起的(de)(de)(de)(de)(de),導(dao)致控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)閥(fa)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)可(ke)能是(shi)(shi)其存(cun)(cun)在(zai)(zai)摩擦、死區、滯后等。這樣的(de)(de)(de)(de)(de)非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)系統經常產生(sheng)非(fei)高(gao)斯和非(fei)線(xian)(xian)(xian)性(xing)(xing)(xing)時間序列。
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