在管道工程中，正確選用電動閥門(men)是滿足使(shi)用(yong)要求的保證條件之一。如果(guo)對所使(shi)用(yong)的電(dian)動閥門(men)選擇不(bu)當,不(bu)僅(jin)會影響(xiang)使(shi)用(yong),而(er)且還會帶來不(bu)良后果(guo)或嚴重的損 失,因此,在管(guan)道工程設(she)計中應正(zheng)確選用(yong)電(dian)動閥門(men)。 

電動閥門除應注意管道參數外，尚應特別注意其工作的環境條件，因為電動閥門中的電動裝置是一機電設備，其工作情況受其工作環境影響很大。 通常情況下，電動閥門所處工作環境有以下幾種：

    1、室內安裝或有防護措施戶(hu)外使用；

    2、戶外露天安裝，有風、砂、雨露、陽光等侵蝕；

    3、具有易(yi)燃、易(yi)爆氣(qi)體或粉(fen)塵環境；

    4、濕熱帶、干熱帶地(di)區環(huan)境；

    5、管道介質(zhi)溫度(du)高達480℃以上；

    6、環境溫度低于-20℃以下；

    7、易遭水淹或浸(jin)水中；

   ; 8、具(ju)有放射(she)性物(wu)質（核電站及放射(she)性物(wu)質試驗裝置）環(huan)境；

    9、艦船上或船塢碼頭（有(you)鹽霧(wu)、霉菌、潮濕(shi)）的環(huan)境(jing)；

    10、具有劇烈振(zhen)動的場合；

    11、易于發生(sheng)火(huo)災(zai)的場合； 

對于(yu)(yu)上(shang)述環境中(zhong)的(de)(de)(de)電(dian)動閥(fa)(fa)門(men)，其電(dian)動裝置(zhi)結(jie)構、材料(liao)和防護(hu)措施皆不(bu)(bu)同(tong)。因(yin)此(ci)，應依據(ju)上(shang)述工作(zuo)環境選(xuan)擇相應的(de)(de)(de)閥(fa)(fa)門(men)電(dian)動裝置(zhi)。根據(ju)工程控(kong)(kong)制(zhi)要求，對電(dian)動閥(fa)(fa)門(men)來(lai)講，其控(kong)(kong)制(zhi)功能(neng)是(shi)由(you)電(dian)動裝置(zhi)來(lai)完成的(de)(de)(de)。使用(yong)電(dian)動閥(fa)(fa)門(men)的(de)(de)(de)目(mu)的(de)(de)(de)，就是(shi)對閥(fa)(fa)門(men)的(de)(de)(de)開、閉(bi)以及調節(jie)聯動實現(xian)非人(ren)工的(de)(de)(de)電(dian)氣控(kong)(kong)制(zhi)或(huo)計算機(ji) 控(kong)(kong)制(zhi)。目(mu)前的(de)(de)(de)電(dian)動裝置(zhi)使用(yong)已不(bu)(bu)只(zhi)是(shi)為了節(jie)省人(ren)力了。由(you)于(yu)(yu)不(bu)(bu)同(tong)廠家產(chan)品的(de)(de)(de)功能(neng)和質量差異較大(da)，因(yin)此(ci)，選(xuan)擇電(dian)動裝置(zhi)和選(xuan)擇所配閥(fa)(fa)門(men)對工程同(tong)等重要。

由于工(gong)業自動(dong)(dong)(dong)(dong)化水(shui)平的(de)(de)(de)(de)要(yao)(yao)求不(bu)(bu)斷(duan)提高，一(yi)方(fang)(fang)(fang)(fang)面對電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門的(de)(de)(de)(de)使(shi)用(yong)(yong)量越來(lai)(lai)越多，另一(yi)方(fang)(fang)(fang)(fang)面對電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)要(yao)(yao)求也越來(lai)(lai)越高，越來(lai)(lai)越復雜。所以電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門在電(dian)(dian)(dian)(dian)氣(qi)(qi)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang) 面的(de)(de)(de)(de)設(she)計(ji)(ji)也在不(bu)(bu)斷(duan)更新。隨著科學技術(shu)(shu)的(de)(de)(de)(de)進(jin)步及計(ji)(ji)算機的(de)(de)(de)(de)普及應(ying)(ying)用(yong)(yong)，新型的(de)(de)(de)(de)、多樣(yang)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)氣(qi)(qi)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang)式(shi)(shi)將不(bu)(bu)斷(duan)地出現(xian)。對電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門總體控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang)面的(de)(de)(de)(de)考慮，應(ying)(ying)注意選擇(ze)電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong) 閥(fa)(fa)(fa)門的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang)式(shi)(shi)。例如，根據工(gong)程(cheng)需(xu)要(yao)(yao)，是(shi)(shi)否使(shi)用(yong)(yong)集中控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang)式(shi)(shi)，還是(shi)(shi)單(dan)臺控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)(fang)(fang)(fang)式(shi)(shi)，是(shi)(shi)否與其(qi)他(ta)設(she)備聯動(dong)(dong)(dong)(dong)，程(cheng)序控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)還是(shi)(shi)應(ying)(ying)用(yong)(yong)計(ji)(ji)算機程(cheng)序控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)等等，其(qi)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)原(yuan)理都 不(bu)(bu)一(yi)樣(yang)。閥(fa)(fa)(fa)門電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)裝置廠家樣(yang)本給出的(de)(de)(de)(de)僅是(shi)(shi)標準(zhun)電(dian)(dian)(dian)(dian)氣(qi)(qi)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)原(yuan)理，因此(ci)使(shi)用(yong)(yong)部(bu)門應(ying)(ying)與電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)裝置生(sheng)產(chan)廠進(jin)行(xing)技術(shu)(shu)交底，明確技術(shu)(shu)要(yao)(yao)求。 此(ci)外，在選擇(ze)電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門時，應(ying)(ying)考慮是(shi)(shi)否附加購(gou)置電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)閥(fa)(fa)(fa)門控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)器(qi)。因為一(yi)般情況，控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)器(qi)是(shi)(shi)需(xu)要(yao)(yao)單(dan)獨購(gou)買的(de)(de)(de)(de)。多數(shu)情況下，采用(yong)(yong)單(dan)臺控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)時，是(shi)(shi)需(xu)要(yao)(yao)購(gou)買控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)器(qi)的(de)(de)(de)(de)， 因為購(gou)買控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)器(qi)比用(yong)(yong)戶自行(xing)設(she)計(ji)(ji)、制(zhi)(zhi)(zhi)造要(yao)(yao)方(fang)(fang)(fang)(fang)便、便宜。當電(dian)(dian)(dian)(dian)氣(qi)(qi)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)性能滿足(zu)不(bu)(bu)了工(gong)程(cheng)設(she)計(ji)(ji)要(yao)(yao)求時，應(ying)(ying)向生(sheng)產(chan)廠提出修(xiu)改(gai)或重(zhong)新設(she)計(ji)(ji)。

閥門(men)電(dian)(dian)動(dong)裝(zhuang)置(zhi)(zhi)(zhi)是實(shi)現(xian)閥門(men)程(cheng)控(kong)(kong)(kong)、自控(kong)(kong)(kong)和遙控(kong)(kong)(kong)不可缺少(shao)的(de)(de)設(she)備，其運動(dong)過程(cheng)可由行程(cheng)、轉(zhuan)矩(ju)或(huo)(huo)軸向推力(li)的(de)(de)大小(xiao)來(lai)控(kong)(kong)(kong)制。由于閥門(men)電(dian)(dian)動(dong)裝(zhuang)置(zhi)(zhi)(zhi)的(de)(de)工作特(te)性和利用率取決于閥門(men)的(de)(de)種類、裝(zhuang)置(zhi)(zhi)(zhi)工作規(gui)范及閥門(men)在管線或(huo)(huo)設(she)備上的(de)(de)位置(zhi)(zhi)(zhi)，因此(ci)，正(zheng)確選擇閥門(men)電(dian)(dian)動(dong)裝(zhuang)置(zhi)(zhi)(zhi)，對防止出現(xian)超負荷(he)現(xian)象(工作轉(zhuan)矩(ju)高(gao)于控(kong)(kong)(kong)制轉(zhuan)矩(ju))至關重要(yao)。通常(chang)，正(zheng)確選擇閥門(men)電(dian)(dian)動(dong)裝(zhuang)置(zhi)(zhi)(zhi)的(de)(de)依據如下：

操(cao)作力(li)矩(ju)操(cao)作力(li)矩(ju)是選擇閥門(men)(men)電動裝(zhuang)置的最主要(yao)參數，電動裝(zhuang)置輸出力(li)矩(ju)應(ying)為閥門(men)(men)操(cao)作最大(da)力(li)矩(ju)的1.2～1.5倍。

操(cao)作推(tui)力閥門電動裝(zhuang)置的(de)主(zhu)機(ji)結構有兩種(zhong)：一(yi)種(zhong)是不(bu)配置推(tui)力盤，直接輸(shu)出(chu)力矩；另一(yi)種(zhong)是配置推(tui)力盤，輸(shu)出(chu)力矩通過推(tui)力盤中(zhong)的(de)閥桿螺母轉換(huan)為輸(shu)出(chu)推(tui)力。

輸(shu)出軸轉(zhuan)動(dong)圈(quan)數(shu)閥(fa)(fa)門電(dian)動(dong)裝置輸(shu)出軸轉(zhuan)動(dong)圈(quan)數(shu)的(de)多(duo)少與閥(fa)(fa)門的(de)公稱通徑、閥(fa)(fa)桿螺距(ju)、螺紋頭(tou)數(shu)有關(guan)，要按(an)M＝H／ZS計算(M為電(dian)動(dong)裝置應滿足的(de)總(zong)轉(zhuan)動(dong)圈(quan)數(shu)，H為閥(fa)(fa)門開啟高度，S為閥(fa)(fa)桿傳(chuan)動(dong)螺紋螺距(ju)，Z為閥(fa)(fa)桿螺紋頭(tou)數(shu))。

閥桿直徑對多回轉類明桿閥門，如果電動裝置允許通過的最大閥桿直徑不能通過所配閥門的閥桿，便不能組裝成電動閥門。因此，電動裝置空心輸出軸的內徑必須大于明桿閥門的閥桿外徑。對部分回轉閥門以及多回轉閥門中的暗桿閥門，雖不用考慮閥桿直徑的通過問題，但在選配時亦應充分考慮閥桿直徑與鍵槽的尺寸，使組裝后能正常工作。

輸(shu)出轉速(su)閥門的啟閉速(su)度若(ruo)過(guo)快，易(yi)產生水(shui)擊現象。因此，應根據不同使用(yong)條件，選擇恰當的啟閉速(su)度。

閥門(men)(men)電(dian)(dian)(dian)動(dong)(dong)裝置(zhi)(zhi)有(you)其特殊要求，即(ji)必須能夠限(xian)定(ding)轉(zhuan)(zhuan)(zhuan)矩或軸向力(li)。通常(chang)閥門(men)(men)電(dian)(dian)(dian)動(dong)(dong)裝置(zhi)(zhi)采用(yong)限(xian)制轉(zhuan)(zhuan)(zhuan)矩的(de)(de)(de)連(lian)(lian)軸器。當電(dian)(dian)(dian)動(dong)(dong)裝置(zhi)(zhi)規格確(que)定(ding)之后，其控制轉(zhuan)(zhuan)(zhuan)矩也就(jiu)確(que)定(ding)了。一般(ban)在預先確(que)定(ding)的(de)(de)(de)時間內運行，電(dian)(dian)(dian)機(ji)(ji)不會(hui)超(chao)負荷(he)(he)。但如出現下列情況便(bian)可能導(dao)致超(chao)負荷(he)(he)：一是電(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)壓(ya)低，得不到(dao)所需的(de)(de)(de)轉(zhuan)(zhuan)(zhuan)矩，使電(dian)(dian)(dian)機(ji)(ji)停(ting)止轉(zhuan)(zhuan)(zhuan)動(dong)(dong)；二(er)是錯誤地調(diao)定(ding)轉(zhuan)(zhuan)(zhuan)矩限(xian)制機(ji)(ji)構，使其大(da)(da)(da)于停(ting)止的(de)(de)(de)轉(zhuan)(zhuan)(zhuan)矩，造成連(lian)(lian)續產生(sheng)過大(da)(da)(da)轉(zhuan)(zhuan)(zhuan)矩，使電(dian)(dian)(dian)機(ji)(ji)停(ting)止轉(zhuan)(zhuan)(zhuan)動(dong)(dong)；三是斷(duan)續使用(yong)，產生(sheng)的(de)(de)(de)熱量積蓄，超(chao)過了電(dian)(dian)(dian)機(ji)(ji)的(de)(de)(de)允許溫升值；四(si)是因某(mou)種原因轉(zhuan)(zhuan)(zhuan)矩限(xian)制機(ji)(ji)構電(dian)(dian)(dian)路發(fa)生(sheng)故障，使轉(zhuan)(zhuan)(zhuan)矩過大(da)(da)(da)；五是使用(yong)環境溫度過高，相對使電(dian)(dian)(dian)機(ji)(ji)熱容量下降(jiang)。

過去對電(dian)(dian)機(ji)進行(xing)保(bao)護的(de)辦法(fa)是使用熔(rong)斷(duan)器(qi)、過流(liu)繼(ji)(ji)電(dian)(dian)器(qi)、熱繼(ji)(ji)電(dian)(dian)器(qi)、恒溫器(qi)等，但這(zhe)(zhe)些(xie)辦法(fa)各有利弊。對電(dian)(dian)動裝置這(zhe)(zhe)種(zhong)(zhong)(zhong)變負荷設備，絕對可靠的(de)保(bao)護辦法(fa)是沒有的(de)。因此，必須采取(qu)各種(zhong)(zhong)(zhong)組(zu)合方式，歸納起來有兩種(zhong)(zhong)(zhong)：一是對電(dian)(dian)機(ji)輸(shu)入電(dian)(dian)流(liu)的(de)增(zeng)減(jian)進行(xing)判斷(duan)；二是對電(dian)(dian)機(ji)本身發熱情(qing)況進行(xing)判斷(duan)。這(zhe)(zhe)兩種(zhong)(zhong)(zhong)方式，無論那種(zhong)(zhong)(zhong)都要考慮電(dian)(dian)機(ji)熱容量(liang)給定的(de)時間余量(liang)。

通常，過(guo)負荷(he)(he)的基本保護(hu)(hu)方法是：對(dui)(dui)電機連(lian)續運轉或點動操作(zuo)的過(guo)負荷(he)(he)保護(hu)(hu)，采(cai)用(yong)恒溫器(qi)(qi)(qi)(qi)；對(dui)(dui)電機堵(du)轉的保護(hu)(hu)，采(cai)用(yong)熱繼(ji)電器(qi)(qi)(qi)(qi)；對(dui)(dui)短路(lu)事故，采(cai)用(yong)熔斷器(qi)(qi)(qi)(qi)或過(guo)流(liu)繼(ji)電器(qi)(qi)(qi)(qi)。