目前(qian)，中(zhong)(zhong)頻感應(ying)爐已廣泛應(ying)用(yong)于工業(ye)領域(yu)，有必(bi)要進(jin)一(yi)步加強(qiang)對中(zhong)(zhong)頻感應(ying)爐的(de)(de)研究。但是，就目前(qian)的(de)(de)情況而言(yan)，在(zai)申請(qing)過(guo)程中(zhong)(zhong)還存在(zai)一(yi)些問題(ti)，有必(bi)要采取有效的(de)(de)措施加以(yi)控制。在(zai)此基礎(chu)上，對中(zhong)(zhong)頻感應(ying)爐在(zai)工業(ye)上的(de)(de)應(ying)用(yong)和維(wei)護進(jin)行了分(fen)析(xi)。

1 感應爐的組成

(1)系(xi)(xi)統的組成(cheng)。中頻(pin)(pin)感(gan)應爐(lu)主(zhu)要由電(dian)控(kong)、爐(lu)體(ti)、絕緣電(dian)極軸、真空液壓(ya)系(xi)(xi)統、循環水系(xi)(xi)統等組成(cheng)。(2)工作原理。中頻(pin)(pin)感(gan)應爐(lu)主(zhu)要是通(tong)(tong)(tong)過(guo)(guo)(guo)三(san)相工頻(pin)(pin)交(jiao)(jiao)流(liu)電(dian)通(tong)(tong)(tong)過(guo)(guo)(guo)整流(liu)部分變(bian)成(cheng)直流(liu)，然(ran)后(hou)通(tong)(tong)(tong)過(guo)(guo)(guo)逆(ni)變(bian)部分進入中頻(pin)(pin)交(jiao)(jiao)流(liu)，通(tong)(tong)(tong)過(guo)(guo)(guo)電(dian)容(rong)器組電(dian)壓(ya)進入感(gan)應線(xian)圈，在線(xian)圈中產生(sheng)(sheng)磁路，通(tong)(tong)(tong)過(guo)(guo)(guo)磁線(xian)切(qie)割感(gan)應環中的有色(se)(se)金(jin)屬，有色(se)(se)金(jin)屬產生(sheng)(sheng)換熱(re)(re)，從而使(shi)有色(se)(se)金(jin)屬加熱(re)(re)熔化一種(zhong)電(dian)加熱(re)(re)設備(bei)。

2 中頻感應爐在工業上的應用

2.1 中(zhong)頻電源頻率(lv)的選擇

當(dang)中頻電(dian)(dian)(dian)源(yuan)頻率(lv)(lv)(lv)(lv)增(zeng)加時(shi)，由電(dian)(dian)(dian)荷形成的閉路電(dian)(dian)(dian)路中的磁線切割充電(dian)(dian)(dian)速度會(hui)增(zeng)加，渦流值會(hui)增(zeng)加，因此加熱(re)(re)(re)效果(guo)顯著。研究表(biao)明，供電(dian)(dian)(dian)頻率(lv)(lv)(lv)(lv)越高(gao)(gao)，效率(lv)(lv)(lv)(lv)越高(gao)(gao)，但(dan)當(dang)效率(lv)(lv)(lv)(lv)接近90%時(shi)，供電(dian)(dian)(dian)頻率(lv)(lv)(lv)(lv)的提(ti)高(gao)(gao)對效率(lv)(lv)(lv)(lv)的影(ying)響不大。同時(shi)，由于表(biao)皮(pi)效應的存(cun)在(zai)(zai)，直(zhi)接加熱(re)(re)(re)層(ceng)的深(shen)度與電(dian)(dian)(dian)源(yuan)的頻率(lv)(lv)(lv)(lv)成反比。通過(guo)長(chang)時(shi)間的導電(dian)(dian)(dian)，工件的表(biao)面和(he)(he)芯部(bu)可以得到(dao)接近的溫度，但(dan)熱(re)(re)(re)效率(lv)(lv)(lv)(lv)會(hui)降(jiang)低。導致熱(re)(re)(re)效率(lv)(lv)(lv)(lv)下降(jiang)的主要(yao)原因是傳熱(re)(re)(re)時(shi)間過(guo)長(chang)，熱(re)(re)(re)在(zai)(zai)周圍(wei)介質中的損失。考慮到(dao)負載的大小對電(dian)(dian)(dian)能和(he)(he)熱(re)(re)(re)效率(lv)(lv)(lv)(lv)的影(ying)響，應合(he)理(li)選擇中頻電(dian)(dian)(dian)源(yuan)的頻率(lv)(lv)(lv)(lv)，即中頻電(dian)(dian)(dian)源(yuan)的頻率(lv)(lv)(lv)(lv)不應過(guo)大或過(guo)小。

2.2 電力變壓器(qi)與中頻電源的匹配

更(geng)合理的(de)(de)(de)(de)(de)(de)(de)匹配(pei)應是變壓(ya)(ya)(ya)器(qi)容(rong)(rong)量(liang)略大于(yu)中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)額定(ding)功(gong)率(lv)(lv)(lv)(lv)。如果(guo)電(dian)(dian)(dian)(dian)(dian)力變壓(ya)(ya)(ya)器(qi)的(de)(de)(de)(de)(de)(de)(de)容(rong)(rong)量(liang)超(chao)過(guo)中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)額定(ding)容(rong)(rong)量(liang)，就會(hui)(hui)造成(cheng)資(zi)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)浪費，但如果(guo)變壓(ya)(ya)(ya)器(qi)的(de)(de)(de)(de)(de)(de)(de)容(rong)(rong)量(liang)等于(yu)甚(shen)至小于(yu)中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)本(ben)身的(de)(de)(de)(de)(de)(de)(de)額定(ding)容(rong)(rong)量(liang)，由于(yu)變壓(ya)(ya)(ya)器(qi)的(de)(de)(de)(de)(de)(de)(de)容(rong)(rong)量(liang)相(xiang)對較小，中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)限值(zhi)會(hui)(hui)適當(dang)降(jiang)低，系(xi)統(tong)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)效(xiao)率(lv)(lv)(lv)(lv)和熱效(xiao)率(lv)(lv)(lv)(lv)會(hui)(hui)損失(shi)。如果(guo)中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)限值(zhi)不(bu)(bu)改變，在充電(dian)(dian)(dian)(dian)(dian)滿的(de)(de)(de)(de)(de)(de)(de)情況下(xia)(xia)(xia)，電(dian)(dian)(dian)(dian)(dian)力變壓(ya)(ya)(ya)器(qi)處于(yu)過(guo)載運行狀態(tai)，壓(ya)(ya)(ya)降(jiang)不(bu)(bu)能嚴(yan)(yan)重保證(zheng)中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，電(dian)(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)甚(shen)至會(hui)(hui)出(chu)現(xian)360 V以下(xia)(xia)(xia)。熱效(xiao)率(lv)(lv)(lv)(lv)的(de)(de)(de)(de)(de)(de)(de)嚴(yan)(yan)重降(jiang)低將使系(xi)統(tong)的(de)(de)(de)(de)(de)(de)(de)總效(xiao)率(lv)(lv)(lv)(lv)嚴(yan)(yan)重下(xia)(xia)(xia)降(jiang)。其原因是中頻(pin)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)過(guo)低，在相(xiang)同負(fu)載下(xia)(xia)(xia)，電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)功(gong)率(lv)(lv)(lv)(lv)與(yu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)平方(fang)成(cheng)正(zheng)比，輸(shu)出(chu)功(gong)率(lv)(lv)(lv)(lv)嚴(yan)(yan)重不(bu)(bu)足，同時降(jiang)低了(le)電(dian)(dian)(dian)(dian)(dian)能效(xiao)率(lv)(lv)(lv)(lv)和熱效(xiao)率(lv)(lv)(lv)(lv)。

2.3 感(gan)應繞(rao)組和爐(lu)襯的優化設計

不(bu)同的(de)(de)(de)繞(rao)組匝數、匝間距(ju)離等都(dou)會影(ying)響電爐(lu)(lu)的(de)(de)(de)冶煉效率。另外，爐(lu)(lu)襯(chen)厚度是決定(ding)爐(lu)(lu)膛特性的(de)(de)(de)主(zhu)要(yao)(yao)參數。爐(lu)(lu)襯(chen)應盡可(ke)能薄(bo)，以(yi)便有更高的(de)(de)(de)電效率和更大的(de)(de)(de)輸入功率，以(yi)滿足電爐(lu)(lu)的(de)(de)(de)電氣特性。為(wei)了保持襯(chen)里的(de)(de)(de)強度，延長襯(chen)里的(de)(de)(de)使(shi)用壽(shou)(shou)命，考(kao)慮(lv)到金屬液體(ti)機械對襯(chen)里的(de)(de)(de)侵蝕(shi)，要(yao)(yao)求襯(chen)里的(de)(de)(de)厚度。因(yin)此，選擇合(he)適的(de)(de)(de)爐(lu)(lu)襯(chen)厚度，不(bu)僅要(yao)(yao)考(kao)慮(lv)爐(lu)(lu)膛的(de)(de)(de)電氣特性，而且要(yao)(yao)保證爐(lu)(lu)襯(chen)的(de)(de)(de)使(shi)用壽(shou)(shou)命。

2.4 執行正確(que)的熔(rong)煉(lian)操作(zuo)

為了加速配料的熔化，應注意充電的方法。需要充分利用爐膛空間，裝載大大小小的爐料。由于感應爐爐料的流量分布不均勻，熔劑密度越接近坩堝壁，坩堝的中心線越大，電勢和電流的外層越大，即“表皮效應”。一般情況下，爐膛內充滿了小藥量，在坩堝壁附近裝上了大藥量，爐底和中間安裝了小裝藥量。中頻電源一般都有必要的電壓和電流限制保護，在裝料時，爐子可先安裝約2≤3充電，快速加熱充電，溫度迅速超過居里點，然后充電阻抗增大，電流在電流限值范圍內，電爐可按額定功率運行，然后再加1≤3充電，從而縮短限流時間。在整個熔煉過程中，必須減少不必要的電壓限制時間，避免因爐料尺寸和長度的不同而造成的“搭接”，使熔爐出現高頻電壓和電壓極限，如果功率不上升，熔煉速度會減慢。
 

3 加強維修

3.1 日常維護

(1)爐膛：開爐前首先(xian)測量(liang)爐膛深度和最大處直徑并做好記(ji)錄，仔細查看爐襯有無(wu)裂紋、破損，及時修補破損的爐口(kou)及爐嘴，第(di)一爐鐵水(shui)(shui)化(hua)好后檢(jian)(jian)測漏(lou)(lou)爐報警裝置。(2)電(dian)氣：全(quan)面檢(jian)(jian)查控制主(zhu)(zhu)板、脈沖主(zhu)(zhu)板、晶(jing)閘管(guan)、電(dian)阻、電(dian)容(rong)、電(dian)抗器、銅排(pai)、換向電(dian)感(gan)等，確保(bao)無(wu)開路、短(duan)路、松動(dong)、虛(xu)焊(han)、漏(lou)(lou)液等現象。(3)灰塵：用風對(dui)斷路器、晶(jing)閘管(guan)、電(dian)抗器、電(dian)容(rong)器、感(gan)應(ying)線圈(quan)外圍進行(xing)一次全(quan)面吹掃。(4)循環水(shui)(shui)：閥門開關準確、水(shui)(shui)管(guan)無(wu)漏(lou)(lou)水(shui)(shui)，水(shui)(shui)壓力(li)0.1～0.2MPa，水(shui)(shui)位(wei)1/3～1/2，進水(shui)(shui)溫(wen)度不(bu)超過3 5℃，出(chu)水(shui)(shui)溫(wen)度不(bu)超過6 5℃。純(chun)水(shui)(shui)導(dao)電(dian)率(lv)不(bu)超過600μΩ/cm。

3.2 定期維護

(1)元件測(ce)量(liang)(liang)：每(mei)(mei)次安裝整(zheng)流元件要對(dui)晶閘管(guan)控制(zhi)極、陰(yin)間(jian)電(dian)(dian)阻(zu)進行(xing)測(ce)量(liang)(liang)(15～50 Ω為(wei)正常)，阻(zu)值接近的(de)串裝在一起(qi)，陽、陰(yin)極間(jian)阻(zu)值幾(ji)十兆歐(ou)為(wei)完好，阻(zu)值為(wei)無窮(qiong)大或者零多認(ren)為(wei)此元件損壞。(2)系(xi)統校準(zhun)：每(mei)(mei)三月對(dui)系(xi)統的(de)直(zhi)流電(dian)(dian)壓、直(zhi)流電(dian)(dian)流、中頻電(dian)(dian)壓、換向角度、過流整(zheng)定(ding)、過壓整(zheng)定(ding)進行(xing)全(quan)(quan)面(mian)校準(zhun)。(3)灰(hui)塵清理：每(mei)(mei)月用刷子擦拭晶閘管(guan)表(biao)面(mian)、電(dian)(dian)阻(zu)器表(biao)面(mian)、控制(zhi)板表(biao)面(mian)、電(dian)(dian)容器絕緣子表(biao)面(mian)灰(hui)塵。(4)螺栓(shuan)緊固(gu)：對(dui)電(dian)(dian)抗(kang)器、電(dian)(dian)阻(zu)器、電(dian)(dian)抗(kang)器、銅排、水(shui)(shui)冷電(dian)(dian)纜等(deng)連(lian)接處全(quan)(quan)面(mian)緊固(gu)。(5)管(guan)路清洗：每(mei)(mei)兩月反沖洗一次軟水(shui)(shui)循環水(shui)(shui)管(guan)路及(ji)元件，并重新裝新純水(shui)(shui);每(mei)(mei)半年(nian)反沖洗一次外循環水(shui)(shui)管(guan)道、感應線圈、磁軛。老化的(de)膠管(guan)全(quan)(quan)部更換，銹(xiu)蝕嚴重的(de)閥門及(ji)時(shi)更新。

4 結語

總之(zhi)，如何(he)提高中頻感(gan)應(ying)爐系統的安(an)全運行能力(li)，保證系統的正常運行是我們需要(yao)解決的問題，因此(ci)有必要(yao)進一步加強(qiang)對(dui)中頻感(gan)應(ying)爐系統的研究。