近(jin)幾年我國經濟(ji)持(chi)續發展(zhan)，能源問題越(yue)(yue)來越(yue)(yue)來為各行(xing)業(ye)發展(zhan)的摯肘。所(suo)以(yi)節能成為許多行(xing)業(ye)發展(zhan)面(mian)臨的主(zhu)要問題，特別是一些(xie)能耗比(bi)較大(da)的行(xing)業(ye)如注塑(su)機的行(xing)業(ye)等。
目(mu)前絕大多數的(de)(de)注(zhu)塑機(ji)都屬于液(ye)壓傳動注(zhu)塑機(ji)，液(ye)壓傳動系統中的(de)(de)動力(li)由(you)電機(ji)帶動油泵(beng)(beng)(beng)提供(gong)(gong)，其(qi)液(ye)壓油泵(beng)(beng)(beng)為容(rong)積式(shi)油泵(beng)(beng)(beng)，其(qi)供(gong)(gong)油量與油泵(beng)(beng)(beng)的(de)(de)轉(zhuan)(zhuan)速成正比，當油泵(beng)(beng)(beng)馬(ma)達以50HZ恒速運轉(zhuan)(zhuan)時，油泵(beng)(beng)(beng)的(de)(de)供(gong)(gong)油量是不變的(de)(de)，所以稱(cheng)為定(ding)量泵(beng)(beng)(beng)。
一般的(de)(de)塑(su)件的(de)(de)生產(chan)過(guo)程中有(you)下面(mian)幾(ji)個環(huan)節：鎖模、射膠、熔(rong)膠、保(bao)壓(ya)(ya)、冷卻(que)、開模。注塑(su)機在不同工(gong)序(xu)下需(xu)要的(de)(de)流(liu)量(liang)(liang)(liang)和(he)(he)壓(ya)(ya)力不同，須(xu)依靠流(liu)量(liang)(liang)(liang)閥和(he)(he)壓(ya)(ya)力閥調節不同工(gong)序(xu)所須(xu)的(de)(de)流(liu)量(liang)(liang)(liang)和(he)(he)壓(ya)(ya)力，當工(gong)作所需(xu)流(liu)量(liang)(liang)(liang)較(jiao)小時(shi)，油(you)泵(beng)供(gong)油(you)量(liang)(liang)(liang)大于執行(xing)元件所需(xu)的(de)(de)油(you)量(liang)(liang)(liang)，多余的(de)(de)處于高壓(ya)(ya)狀態下的(de)(de)液壓(ya)(ya)油(you)全部經(jing)溢流(liu)閥回流(liu)，大量(liang)(liang)(liang)的(de)(de)能量(liang)(liang)(liang)通過(guo)油(you)的(de)(de)溫(wen)升消耗掉(diao)。這樣(yang)既(ji)加劇了各(ge)種閥門的(de)(de)磨(mo)損，又造成油(you)溫(wen)過(guo)高，而且為(wei)了降低油(you)溫(wen)，往(wang)(wang)往(wang)(wang)還需(xu)要額外(wai)的(de)(de)冷卻(que)水循環(huan)，造成能量(liang)(liang)(liang)的(de)(de)進(jin)一步浪費。
塑(su)機節能改造原理：
①注(zhu)塑(su)機(ji)(ji)(ji)成(cheng)型(xing)的(de)(de)工(gong)(gong)藝過程(cheng)注(zhu)塑(su)機(ji)(ji)(ji)主要(yao)用(yong)于熱塑(su)料的(de)(de)成(cheng)型(xing)加(jia)工(gong)(gong).注(zhu)塑(su)機(ji)(ji)(ji)成(cheng)型(xing)工(gong)(gong)藝是一(yi)(yi)個按(an)照(zhao)預(yu)(yu)定(ding)(ding)的(de)(de)周(zhou)期性動(dong)作過程(cheng),即(ji)以合(he)模等—射(she)(she)嘴前(qian)進(jin)—射(she)(she)膠(jiao)—保壓(ya)(ya)(ya)—溶膠(jiao),冷卻--開模—頂出制品—頂桿退回—合(he)模等加(jia)工(gong)(gong)工(gong)(gong)序(xu)達到某件產品成(cheng)型(xing).注(zhu)塑(su)機(ji)(ji)(ji)通(tong)(tong)常采用(yong)減液(ye)(ye)壓(ya)(ya)(ya)傳動(dong),其(qi)(qi)結構包含注(zhu)射(she)(she)裝(zhuang)置(zhi),開合(he)模裝(zhuang)置(zhi),液(ye)(ye)壓(ya)(ya)(ya)傳動(dong)裝(zhuang)置(zhi)和(he)電氣控制裝(zhuang)置(zhi),后者(zhe)的(de)(de)作用(yong)是保證注(zhu)塑(su)機(ji)(ji)(ji)按(an)工(gong)(gong)藝過程(cheng)以預(yu)(yu)完定(ding)(ding)每(mei)個工(gong)(gong)序(xu)的(de)(de)要(yao)求(壓(ya)(ya)(ya)力,速(su)度,溫(wen)度,時(shi)間(jian),位置(zhi))和(he)動(dong)作程(cheng)序(xu)準確有效地工(gong)(gong)作.在傳統的(de)(de)注(zhu)塑(su)機(ji)(ji)(ji)中,液(ye)(ye)壓(ya)(ya)(ya)傳動(dong)裝(zhuang)置(zhi)主要(yao)出油(you)泵,液(ye)(ye)壓(ya)(ya)(ya)控制,壓(ya)(ya)(ya)力電磁比例(li)(li)閥,流量(liang)(liang)電磁比例(li)(li)閥,各種不同(tong)的(de)(de)動(dong)作油(you)缸,油(you)泵電機(ji)(ji)(ji)及其(qi)(qi)它液(ye)(ye)壓(ya)(ya)(ya)附件和(he)管道組成(cheng),其(qi)(qi)中,油(you)泵是定(ding)(ding)量(liang)(liang)油(you)泵,電動(dong)機(ji)(ji)(ji)通(tong)(tong)常提(ti)供額定(ding)(ding)功率和(he)轉速(su),油(you)泵將(jiang)電動(dong)機(ji)(ji)(ji)所輸(shu)入的(de)(de)機(ji)(ji)(ji)械(xie)能(neng)轉變為壓(ya)(ya)(ya)力能(neng),然后向(xiang)液(ye)(ye)壓(ya)(ya)(ya)系統的(de)(de)液(ye)(ye)壓(ya)(ya)(ya)元件輸(shu)送具有一(yi)(yi)定(ding)(ding)壓(ya)(ya)(ya)力和(he)流量(liang)(liang)的(de)(de)液(ye)(ye)壓(ya)(ya)(ya)油(you),滿(man)足液(ye)(ye)壓(ya)(ya)(ya)執行(xing)機(ji)(ji)(ji)構驅(qu)動(dong)負載所需能(neng)量(liang)(liang)的(de)(de)要(yao)求.
②變(bian)頻器(qi)調(diao)速(su)(su)節能(neng)裝置(zhi)的控(kong)制(zhi)(zhi)系統根據注塑(su)機的工藝要求(qiu),利(li)用(yong)(yong)注塑(su)機電(dian)腦的同(tong)步(bu)控(kong)制(zhi)(zhi)信號及電(dian)氣控(kong)制(zhi)(zhi),從注塑(su)機的壓力電(dian)磁(ci)比(bi)例閥(fa)和流量(liang)電(dian)磁(ci)比(bi)例閥(fa)分別取出0-1ADC的模擬電(dian)流信號,直(zhi)接加在變(bian)頻器(qi)專用(yong)(yong)的輸入端,從而改(gai)變(bian)變(bian)頻器(qi)的輸出頻率(lv),即(ji)改(gai)變(bian)油(you)(you)泵(beng)電(dian)機的轉速(su)(su),來改(gai)變(bian)油(you)(you)泵(beng)電(dian)機的輸出流量(liang)Q,滿足注塑(su)機在各個工序中所需的油(you)(you)泵(beng)壓力大(da)小和流量(liang)速(su)(su)度,將傳統的定量(liang)泵(beng)轉變(bian)為量(liang)泵(beng).
調速節(jie)能(neng)裝置的節(jie)能(neng)原理(li)：
①變頻節能(neng)由(you)流(liu)體力學(xue)可知,P(功(gong)(gong)率(lv)(lv))=H(壓(ya)力),流(liu)量(liang)(liang)(liang)Q與(yu)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)n的(de)(de)(de)一次(ci)方(fang)(fang)成正比(bi)(bi),壓(ya)力H與(yu)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)n的(de)(de)(de)平方(fang)(fang)成正比(bi)(bi),功(gong)(gong)率(lv)(lv)P與(yu)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)n的(de)(de)(de)立(li)方(fang)(fang)成正比(bi)(bi),Q/Q=n/n,H/H=n/n式中:Q-油(you)(you)泵(beng)(beng)(beng)的(de)(de)(de)額定(ding)流(liu)量(liang)(liang)(liang),H-油(you)(you)泵(beng)(beng)(beng)的(de)(de)(de)額定(ding)壓(ya)力,P-油(you)(you)泵(beng)(beng)(beng)電(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)(de)額定(ding)功(gong)(gong)率(lv)(lv),n油(you)(you)泵(beng)(beng)(beng)電(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)(de)額定(ding)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su).由(you)上述(shu)公式可知,如(ru)果油(you)(you)泵(beng)(beng)(beng)的(de)(de)(de)功(gong)(gong)率(lv)(lv)一定(ding),當要求(qiu)調節流(liu)量(liang)(liang)(liang)Q下(xia)降時(shi),轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)n可成比(bi)(bi)例下(xia)降,此(ci)時(shi)油(you)(you)泵(beng)(beng)(beng)的(de)(de)(de)軸輸出功(gong)(gong)率(lv)(lv)P是成立(li)方(fang)(fang)關系(xi)下(xia)降,即油(you)(you)泵(beng)(beng)(beng)電(dian)(dian)(dian)機(ji)(ji)(ji)耗電(dian)(dian)(dian)功(gong)(gong)率(lv)(lv)P與(yu)其轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)n近似成立(li)方(fang)(fang)關系(xi).例如(ru):某注(zhu)塑機(ji)(ji)(ji)油(you)(you)泵(beng)(beng)(beng)電(dian)(dian)(dian)機(ji)(ji)(ji)額定(ding)功(gong)(gong)率(lv)(lv)為55KW,則當轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)下(xia)降到原(yuan)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)的(de)(de)(de)4/5時(shi),其耗電(dian)(dian)(dian)量(liang)(liang)(liang)為28.16KW,省電(dian)(dian)(dian)48.8%;當轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)下(xia)降到原(yuan)轉(zhuan)(zhuan)(zhuan)(zhuan)速(su)(su)(su)的(de)(de)(de)1/2時(shi),其耗電(dian)(dian)(dian)量(liang)(liang)(liang)僅用6.875KW,省電(dian)(dian)(dian)87.5%.
②動態功(gong)(gong)(gong)率(lv)(lv)(lv)因數補(bu)償(chang)節能無功(gong)(gong)(gong)率(lv)(lv)(lv)不但增加(jia)線損(sun)和(he)設備的(de)(de)發(fa)熱,更主要(yao)的(de)(de)是因為(wei)功(gong)(gong)(gong)率(lv)(lv)(lv)因數的(de)(de)降(jiang)低導致(zhi)電(dian)網(wang)的(de)(de)有(you)(you)功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv)的(de)(de)降(jiang)低.由公式(shi)S=P+Q, Q=S*SINфP=S*COSф ,其中:S-視在(zai)功(gong)(gong)(gong)率(lv)(lv)(lv),Q-無功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv),P-有(you)(you)功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv),COSф功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv)因數.可知(zhi).當COSф越(yue)大(da),有(you)(you)功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv)P越(yue)大(da).普通定量泵注塑(su)機COSф值在(zai)0.6-0.8之間,而使(shi)用變頻器(qi)調速(su)節能控制裝置(zhi)后, 由于變頻器(qi)內濾波電(dian)容的(de)(de)作用,使(shi)得(de)COSф≈1,從而減小了無功(gong)(gong)(gong)損(sun)耗,增大(da)了電(dian)網(wang)的(de)(de)有(you)(you)功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)(lv).
③軟(ruan)啟(qi)(qi)動(dong)(dong)節(jie)能(neng)(neng)由于電(dian)機(ji)為直接啟(qi)(qi)動(dong)(dong)或(huo)Y/D啟(qi)(qi)動(dong)(dong),啟(qi)(qi)動(dong)(dong)電(dian)流(liu)(liu)(liu)等于(3-7)倍(bei)額定電(dian)流(liu)(liu)(liu),這樣會對(dui)電(dian)機(ji)設(she)(she)備和供(gong)電(dian)電(dian)網(wang)造成嚴重的(de)(de)(de)(de)沖(chong)擊(ji),而且還會對(dui)電(dian)網(wang)量要求過(guo)高,啟(qi)(qi)動(dong)(dong)時產生(sheng)的(de)(de)(de)(de)大電(dian)流(liu)(liu)(liu)和震動(dong)(dong)時對(dui)設(she)(she)備的(de)(de)(de)(de)使用(yong)(yong)壽命極為不利(li),而使用(yong)(yong)變(bian)頻器節(jie)能(neng)(neng)裝置(zhi)后,利(li)用(yong)(yong)變(bian)頻器的(de)(de)(de)(de)軟(ruan)啟(qi)(qi)動(dong)(dong)功能(neng)(neng)將(jiang)使啟(qi)(qi)動(dong)(dong)電(dian)流(liu)(liu)(liu)從零(ling)開始,最大值(zhi)也(ye)不超(chao)過(guo)額定電(dian)流(liu)(liu)(liu),減輕了對(dui)電(dian)網(wang)的(de)(de)(de)(de)沖(chong)擊(ji)和對(dui)電(dian)容(rong)量的(de)(de)(de)(de)要求,延長了設(she)(she)備和模具的(de)(de)(de)(de)使用(yong)(yong)壽命.
