[高低溫試驗箱]高低溫試驗箱的相關操作技巧及操作指南
[高低溫試驗箱]高低溫試驗箱的相(xiang)關操(cao)作技巧(qiao)及操(cao)作指南
高低(di)溫(wen)試(shi)驗箱用于工(gong)業產品高溫(wen)、低(di)溫(wen)的可靠(kao)性試(shi)驗。對電子電工(gong)、汽(qi)車摩托(tuo)、航空航天(tian)、船舶兵器、高等(deng)院校(xiao)、科研(yan)單位等(deng)相關產品的零部件及材料在高溫(wen)、低(di)溫(wen)(交(jiao)變(bian))循環變(bian)化的情況下,檢驗其各項性能指標。試(shi)驗箱由制冷系(xi)統(tong)(tong),加熱系(xi)統(tong)(tong),控制系(xi)統(tong)(tong),濕度系(xi)統(tong)(tong),空氣循環系(xi)統(tong)(tong)和傳感(gan)器系(xi)統(tong)(tong)等(deng)組成,上述(shu)系(xi)統(tong)(tong)分(fen)屬(shu)電氣和機(ji)械制冷兩大方面。
電子(zi)元器(qi)件(jian)型高低溫(wen)試驗箱
溫度控(kong)制對于試驗箱來(lai)說至關重要,通(tong)常通(tong)過1.全(quan)程平(ping)均升降溫速(su)度(即全(quan)程平(ping)均以N度的速(su)率變(bian)化),2.線形升降溫速(su)度(即以每分鐘N度的速(su)率變(bian)化)。來(lai)實(shi)現(xian)快速(su)溫度變(bian)化試驗箱的變(bian)溫速(su)率。
1、全程平均升降(jiang)溫速(su)度:
全程(cheng)平均(jun)速(su)度(du)是(shi)指在(zai)試(shi)驗箱的(de)變溫范圍(wei)內,最高(gao)溫度(du)與(yu)最低溫度(du)之(zhi)差(cha)值(zhi)與(yu)時間之(zhi)比(bi),目前國外各環境(jing)試(shi)驗設備生產廠家提供(gong)的(de)變溫速(su)率(lv)(lv)的(de)技術參數都是(shi)指的(de)全程(cheng)平均(jun)速(su)率(lv)(lv)。
2、線(xian)形升降(jiang)溫(wen)速度:
線(xian)形(xing)(xing)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)指在(zai)任意的(de)每5min時間段(duan)內,能(neng)夠(gou)保(bao)證(zheng)的(de)變溫(wen)(wen)(wen)(wen)速(su)率(lv)。而實際上對(dui)于(yu)快速(su)溫(wen)(wen)(wen)(wen)度(du)(du)變化高低(di)溫(wen)(wen)(wen)(wen)試(shi)(shi)(shi)驗箱來說(shuo),保(bao)證(zheng)線(xian)形(xing)(xing)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)的(de)難度(du)(du)最(zui)(zui)大、最(zui)(zui)關鍵的(de)一段(duan)是,渦街(jie)流量計在(zai)降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)段(duan)最(zui)(zui)后的(de)一個5min的(de)時間段(duan)內,試(shi)(shi)(shi)驗箱可(ke)以達到(dao)的(de)降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)率(lv)。因此試(shi)(shi)(shi)驗設備最(zui)(zui)好具有(you)全(quan)程(cheng)平(ping)均(jun)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)和線(xian)形(xing)(xing)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)(每5min平(ping)均(jun)速(su)度(du)(du))這兩個參數(shu),一般(ban)來說(shuo),線(xian)形(xing)(xing)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)(每5min平(ping)均(jun)速(su)度(du)(du))是全(quan)程(cheng)平(ping)均(jun)升降(jiang)(jiang)(jiang)溫(wen)(wen)(wen)(wen)速(su)度(du)(du)的(de)1/2。
由于高低(di)(di)溫(wen)(wen)(wen)(wen)(wen)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)有恒(heng)定(ding)(ding)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)與交變(bian)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)之分,所以控(kong)制(zhi)方式(shi)也(ye)就(jiu)有了不(bu)同,對于恒(heng)定(ding)(ding)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)來說,其(qi)其(qi)控(kong)制(zhi)方式(shi)為:設(she)定(ding)(ding)一(yi)(yi)個目標(biao)溫(wen)(wen)(wen)(wen)(wen)度(du),試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)具有自動(dong)(dong)恒(heng)溫(wen)(wen)(wen)(wen)(wen)到(dao)目標(biao)溫(wen)(wen)(wen)(wen)(wen)度(du)點的(de)能(neng)力。恒(heng)定(ding)(ding)溫(wen)(wen)(wen)(wen)(wen)濕(shi)度(du)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)的(de)控(kong)制(zhi)控(kong)制(zhi)方式(shi)也(ye)類(lei)似,設(she)定(ding)(ding)一(yi)(yi)個目標(biao)溫(wen)(wen)(wen)(wen)(wen)度(du)、濕(shi)度(du)點,試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)具有自動(dong)(dong)恒(heng)溫(wen)(wen)(wen)(wen)(wen)到(dao)目標(biao)溫(wen)(wen)(wen)(wen)(wen)度(du)、濕(shi)度(du)點的(de)能(neng)力。高、低(di)(di)溫(wen)(wen)(wen)(wen)(wen)交變(bian)試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)具有設(she)定(ding)(ding)一(yi)(yi)條或者(zhe)多條高低(di)(di)溫(wen)(wen)(wen)(wen)(wen)變(bian)化、循環的(de)程序,試(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)有能(neng)力根據預置的(de)曲線完成試(shi)(shi)(shi)(shi)驗(yan)(yan)過(guo)程,并且可以在最大升(sheng)溫(wen)(wen)(wen)(wen)(wen)、降(jiang)溫(wen)(wen)(wen)(wen)(wen)速(su)率(lv)能(neng)力的(de)范圍(wei)內,精確控(kong)制(zhi)升(sheng)溫(wen)(wen)(wen)(wen)(wen)、降(jiang)溫(wen)(wen)(wen)(wen)(wen)的(de)速(su)率(lv),即可以根據設(she)定(ding)(ding)的(de)曲線的(de)斜(xie)率(lv)控(kong)制(zhi)升(sheng)溫(wen)(wen)(wen)(wen)(wen)、降(jiang)溫(wen)(wen)(wen)(wen)(wen)速(su)率(lv)。
交(jiao)(jiao)變(bian)(bian)濕熱試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)也具有(you)預置(zhi)(zhi)溫度(du)(du)、濕度(du)(du)曲線,并且(qie)根(gen)據預置(zhi)(zhi)進行控(kong)制的能(neng)力。當然,交(jiao)(jiao)變(bian)(bian)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)都具有(you)恒定(ding)(ding)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)的功能(neng),但(dan)交(jiao)(jiao)變(bian)(bian)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)的制造成本較高(gao),因為交(jiao)(jiao)變(bian)(bian)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)需配置(zhi)(zhi)有(you)曲線自動記錄裝置(zhi)(zhi)、程(cheng)序控(kong)制儀,還須解決試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)在工作室內溫度(du)(du)較高(gao)的情況(kuang)下開(kai)啟制冷機(ji)等問題,因此,交(jiao)(jiao)變(bian)(bian)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)的價(jia)格(ge)比恒定(ding)(ding)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)的價(jia)格(ge)一般要高(gao)20%以(yi)上。因此,我們應當實事求是(shi)的以(yi)試(shi)(shi)(shi)驗(yan)(yan)(yan)方法(fa)的需要為出(chu)發點,選用恒定(ding)(ding)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)或(huo)者是(shi)交(jiao)(jiao)變(bian)(bian)試(shi)(shi)(shi)驗(yan)(yan)(yan)箱(xiang)(xiang)(xiang)(xiang)(xiang)。
為(wei)什么要使用高低溫(wen)濕熱(re)試驗箱來檢(jian)測(ce)產品?
1)濕(shi)熱對(dui)產品的影響:
潮(chao)(chao)濕(shi)環境(jing)可以引起材(cai)料(liao)(liao)的(de)機(ji)械性能(neng)和(he)(he)(he)化(hua)(hua)學(xue)性能(neng)的(de)變化(hua)(hua),如體膨(peng)脹、機(ji)械強度(du)降(jiang)(jiang)(jiang)低等(deng)。 由于(yu)(yu)吸(xi)潮(chao)(chao),使密封產(chan)(chan)品的(de)密封性能(neng)降(jiang)(jiang)(jiang)低或(huo)遭破壞、產(chan)(chan)品表(biao)面涂敷層剝落、產(chan)(chan)品標記模糊不(bu)清等(deng)。 由于(yu)(yu)凝(ning)露和(he)(he)(he)吸(xi)附作(zuo)(zuo)用(yong)(yong),使絕緣材(cai)料(liao)(liao)的(de)表(biao)面絕緣電(dian)阻下(xia)降(jiang)(jiang)(jiang)。 由于(yu)(yu)水分的(de)吸(xi)收和(he)(he)(he)擴散(san)作(zuo)(zuo)用(yong)(yong),使絕緣材(cai)料(liao)(liao)的(de)體積電(dian)阻下(xia)降(jiang)(jiang)(jiang),從而產(chan)(chan)生漏電(dian)流。 對于(yu)(yu)整機(ji)設(she)備(bei),將(jiang)會導致靈敏度(du)降(jiang)(jiang)(jiang)低、頻率漂移等(deng)。 濕(shi)熱(re)的(de)腐蝕(shi)作(zuo)(zuo)用(yong)(yong)是由于(yu)(yu)空氣中含有少量(liang)的(de)酸、堿性雜質,或(huo)由于(yu)(yu)產(chan)(chan)品表(biao)面附著如焊(han)渣、汗漬等(deng)污染(ran)物(wu)質而引起間(jian)(jian)接的(de)化(hua)(hua)學(xue)和(he)(he)(he)電(dian)化(hua)(hua)學(xue)腐蝕(shi)作(zuo)(zuo)用(yong)(yong)。 對于(yu)(yu)不(bu)同的(de)金(jin)屬(shu)材(cai)料(liao)(liao)、金(jin)屬(shu)和(he)(he)(he)非金(jin)屬(shu)材(cai)料(liao)(liao)之間(jian)(jian),即(ji)使在(zai)(zai)沒有污染(ran)物(wu)質存在(zai)(zai)的(de)條件下(xia),只要有適宜的(de)濕(shi)度(du)條件或(huo)有凝(ning)露,由于(yu)(yu)化(hua)(hua)學(xue)或(huo)電(dian)化(hua)(hua)學(xue)作(zuo)(zuo)用(yong)(yong)的(de)結(jie)果,也會引起不(bu)同程(cheng)度(du)的(de)腐蝕(shi)。
2)濕(shi)度(du)環境效應
1. 材料的膨(peng)脹(zhang)。
2. 物理強度的喪失。
3. 化學性能(neng)的改變。
4. 絕緣材料性能(neng)的退化(hua)。
5. 電性(xing)短路。
6. 活動機件由(you)于腐蝕(shi)及(ji)潤滑劑污濁造成卡死。
7. 金屬材料的氧化腐(fu)蝕。
8. 可(ke)塑性的(de)喪失。
9. 加速化學反應。
10.電子元件的退化(hua)。
國(guo)內(nei)(nei)外環(huan)境試驗箱(xiang)給(gei)出(chu)的(de)濕度(du)(du)指(zhi)標大(da)都(dou)是(shi)(shi)20~98%RH或(huo)30~98%RH,如(ru)果濕熱(re)試驗箱(xiang)沒(mei)有除濕系統,則濕度(du)(du)范圍為60~98%,這一類試驗箱(xiang)只(zhi)能做高(gao)濕試驗,但它的(de)價格低得多。值(zhi)得注(zhu)(zhu)意的(de)是(shi)(shi)在濕度(du)(du)指(zhi)標后面應(ying)該注(zhu)(zhu)明相(xiang)(xiang)應(ying)的(de)溫(wen)度(du)(du)范圍,或(huo)給(gei)出(chu)最低露點溫(wen)度(du)(du)。因(yin)為相(xiang)(xiang)對濕度(du)(du)是(shi)(shi)與溫(wen)度(du)(du)直接(jie)相(xiang)(xiang)關的(de),對于同樣的(de)絕(jue)對含(han)(han)濕量,溫(wen)度(du)(du)越高(gao),相(xiang)(xiang)對濕度(du)(du)就越小,如(ru)絕(jue)對含(han)(han)濕量為5g/Kg(指(zhi)1公(gong)斤干空氣中含(han)(han)有5克的(de)水蒸汽),當溫(wen)度(du)(du)為29℃時,相(xiang)(xiang)對濕度(du)(du)為20%RH,溫(wen)度(du)(du)為6℃時,相(xiang)(xiang)對濕度(du)(du)為90%RH,當溫(wen)度(du)(du)降(jiang)至4℃以下,相(xiang)(xiang)對濕度(du)(du)超過100%,在箱(xiang)體內(nei)(nei)會出(chu)現(xian)結露現(xian)象。
濕(shi)(shi)熱試驗(yan)箱除濕(shi)(shi)系統采用(yong)蒸發(fa)器盤管(guan)露(lu)點溫(wen)度層流接(jie)觸式加濕(shi)(shi)器,對于濕(shi)(shi)度的精度控制(zhi)(zhi),環(huan)境試驗(yan)箱中(zhong)測(ce)量(liang)濕(shi)(shi)度多數(shu)是采用(yong)干(gan)濕(shi)(shi)球法,環(huan)境試驗(yan)設備的制(zhi)(zhi)造標準GB10586要(yao)(yao)求,相對濕(shi)(shi)度偏差應在+2-3%RH。為滿足濕(shi)(shi)度控制(zhi)(zhi)精度的要(yao)(yao)求,濕(shi)(shi)度試驗(yan)箱的溫(wen)度控制(zhi)(zhi)精度較高,溫(wen)度波動一般小(xiao)于±0.2℃。否則很難達(da)到(dao)濕(shi)(shi)度控制(zhi)(zhi)精度的要(yao)(yao)求。
廣東劍喬試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)設備(bei)有(you)限公司是專注于振(zhen)動及(ji)環境試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)設備(bei)研(yan)發、生產(chan)(chan)、銷(xiao)售大(da)型生產(chan)(chan)廠家,主營產(chan)(chan)品:振(zhen)動臺(tai)(tai)、振(zhen)動試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)機(ji)、振(zhen)動試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)臺(tai)(tai)、沖(chong)(chong)擊(ji)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)臺(tai)(tai)、沖(chong)(chong)擊(ji)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)機(ji)、老化房、恒(heng)(heng)(heng)溫(wen)恒(heng)(heng)(heng)濕(shi)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)室、恒(heng)(heng)(heng)溫(wen)恒(heng)(heng)(heng)濕(shi)機(ji)、快速(su)溫(wen)變試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)、高低(di)溫(wen)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)、冷(leng)熱(re)沖(chong)(chong)擊(ji)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)、冷(leng)熱(re)沖(chong)(chong)擊(ji)箱(xiang)、恒(heng)(heng)(heng)溫(wen)恒(heng)(heng)(heng)濕(shi)箱(xiang)、恒(heng)(heng)(heng)溫(wen)恒(heng)(heng)(heng)濕(shi)試(shi)(shi)(shi)(shi)(shi)驗(yan)(yan)箱(xiang)等(deng)產(chan)(chan)品。