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| 高低溫試驗箱復疊式冷凍機技術知識介紹 |
| 來源：諾冰制冷 發布時間：2016-8-15 |
高(gao)低(di)溫(wen)(wen)試驗(yan)箱(xiang)復疊式(shi)冷(leng)(leng)(leng)(leng)凍機通常由(you)兩(liang)個(ge)(ge)部(bu)(bu)(bu)分(fen)(fen)(也可(ke)由(you)三個(ge)(ge)部(bu)(bu)(bu)分(fen)(fen)) 組(zu)成，分(fen)(fen)別稱為(wei)(wei)高(gao)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)及(ji)低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)。高(gao)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)使(shi)用中溫(wen)(wen)制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)，低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)使(shi)用低(di)溫(wen)(wen)制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)，而(er)每(mei)一(yi)部(bu)(bu)(bu)分(fen)(fen)都是(shi)(shi)一(yi)個(ge)(ge)完整的單級或雙(shuang)級壓縮制(zhi)冷(leng)(leng)(leng)(leng)系(xi)(xi)統(tong)(tong)(tong)。高(gao)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)系(xi)(xi)統(tong)(tong)(tong)中制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)的蒸(zheng)發是(shi)(shi)用來使(shi)低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)系(xi)(xi)統(tong)(tong)(tong)中制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)冷(leng)(leng)(leng)(leng)凝(ning)，而(er)只有低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)系(xi)(xi)統(tong)(tong)(tong)的制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)在蒸(zheng)發時才制(zhi)取冷(leng)(leng)(leng)(leng)量。高(gao)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)和(he)低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)用一(yi)個(ge)(ge)冷(leng)(leng)(leng)(leng)凝(ning)蒸(zheng)發器聯(lian)系(xi)(xi)起(qi)來,它(ta)既是(shi)(shi)高(gao)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)的蒸(zheng)發器,又是(shi)(shi)低(di)溫(wen)(wen)部(bu)(bu)(bu)分(fen)(fen)的冷(leng)(leng)(leng)(leng)凝(ning)器。高(gao)低(di)溫(wen)(wen)試驗(yan)箱(xiang)復疊制(zhi)冷(leng)(leng)(leng)(leng)機組(zu)大都以R22/ R404為(wei)(wei)制(zhi)冷(leng)(leng)(leng)(leng)劑(ji)(ji)。
高低溫試驗(yan)箱(xiang)復疊式冷凍機有兩個比較重(zhong)要的知識點：
一、中(zhong)間溫度的(de)確(que)定
復(fu)疊式制(zhi)冷循(xun)環中(zhong)(zhong)中(zhong)(zhong)間(jian)溫度(du)(du)的(de)(de)(de)確定應根據(ju)制(zhi)冷系(xi)(xi)數(shu)(shu)最大(da)或(huo)各個壓縮(suo)機(ji)壓力(li)比大(da)致相(xiang)等的(de)(de)(de)原則。前者對能量利用最經濟,后(hou)者對壓縮(suo)機(ji)氣(qi)缸工作容積(ji)的(de)(de)(de)利用率較高(即輸氣(qi)系(xi)(xi)數(shu)(shu)較大(da)) 。由于(yu)中(zhong)(zhong)間(jian)溫度(du)(du)在一定范圍內變動時對制(zhi)泠(ling)系(xi)(xi)數(shu)(shu)影(ying)響并不大(da),故按各級壓力(li)比大(da)致相(xiang)等的(de)(de)(de)原則來(lai)確定中(zhong)(zhong)間(jian)溫度(du)(du)似乎(hu)更(geng)為(wei)合(he)理(li)。
二(er)、膨脹容器
高低溫試驗箱復疊式冷凍機停止運轉時,由于系統內的溫度升高到了環境溫度，低溫制冷劑全部氣化成過熱蒸汽，并且將高于規定的最大工作壓力，這種情況是不允許的。因此要在系統中接入一個膨脹容器，以便在停機后大部分的制冷劑蒸汽進入膨脹容器中，膨脹容器可以接到吸氣管上，也可以接到排氣管上，接到吸氣管上時，膨脹容器所需要的容積較小，因而比較合理 。
膨脹容器的容積可按如下方法計算:
V p = ( Gd*vp - V d)*vd/(vd – vp)
式(shi)中: V d 為(wei)不計膨(peng)(peng)脹(zhang)容器(qi)容積時，低(di)溫(wen)(wen)(wen)部分的制(zhi)冷(leng)系(xi)(xi)統(tong)(tong)總(zong)容積(m3) ; vp 為(wei)設計溫(wen)(wen)(wen)度、設計壓力下(xia)低(di)溫(wen)(wen)(wen)系(xi)(xi)統(tong)(tong)制(zhi)冷(leng)劑過熱(re)氣(qi)體比(bi)容(m3/ kg) ; v d 為(wei)設計溫(wen)(wen)(wen)度、吸氣(qi)壓力下(xia)低(di)溫(wen)(wen)(wen)系(xi)(xi)統(tong)(tong)制(zhi)冷(leng)劑過熱(re)氣(qi)體比(bi)容(m3/ kg) ; Gd 為(wei)不計膨(peng)(peng)脹(zhang)容器(qi)容積時,低(di)溫(wen)(wen)(wen)系(xi)(xi)統(tong)(tong)制(zhi)冷(leng)劑充注量(kg) 。(end) |
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