一、真空

真(zhen)空(kong)(kong)(kong)(kong)室合蓋，真(zhen)空(kong)(kong)(kong)(kong)泵(beng)(beng)工作，真(zhen)空(kong)(kong)(kong)(kong)室開始抽真(zhen)空(kong)(kong)(kong)(kong)，包(bao)裝袋內同(tong)時(shi)真(zhen)空(kong)(kong)(kong)(kong)，真(zhen)空(kong)(kong)(kong)(kong)表指針(zhen)上升，達到額定真(zhen)空(kong)(kong)(kong)(kong)度(du)（有時(shi)間繼電器控制(zhi)）真(zhen)空(kong)(kong)(kong)(kong)泵(beng)(beng)停止工作，真(zhen)空(kong)(kong)(kong)(kong)停。在(zai)真(zhen)空(kong)(kong)(kong)(kong)工作的同(tong)時(shi)，電磁閥工作，熱封氣室真(zhen)空(kong)(kong)(kong)(kong)，熱壓架(jia)保持(chi)原位

二、熱封

電磁閥(fa)斷開，外界大氣通過其上部進(jin)氣孔進(jin)入(ru)熱(re)風氣室(shi)(shi)，利用真(zhen)空室(shi)(shi)內同(tong)熱(re)封(feng)氣室(shi)(shi)之(zhi)間(jian)壓力(li)差(cha)，熱(re)封(feng)氣室(shi)(shi)充氣膨脹(zhang)，使(shi)其上熱(re)壓架(jia)下移，壓住袋口；同(tong)時熱(re)封(feng)變(bian)壓器(qi)工作(zuo)，開始(shi)封(feng)口；在(zai)此同(tong)時，時間(jian)繼電器(qi)工作(zuo)，數秒后熱(re)封(feng)結束。

三、回氣

二(er)位(wei)二(er)通電磁閥通，大氣進(jin)入真(zhen)空室，真(zhen)空表指針(zhen)回到零，熱(re)壓架(jia)依(yi)靠(kao)復(fu)位(wei)彈簧復(fu)位(wei)，真(zhen)空室開(kai)蓋

四、循環

將上真(zhen)空室(shi)移至另一(yi)真(zhen)空室(shi)，即(ji)進入下一(yi)個(ge)工作過程，左右兩室(shi)交(jiao)替工作，循環往(wang)復