低(di)(di)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)裝置如真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)輸送(song)、真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)浸漬(zi)、真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)過濾、真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)單調、真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)脫氣(qi)(qi)(qi)（鋼(gang)水(shui)處(chu)置）等(deng)(deng)懇求具有工作壓力(li)高、排氣(qi)(qi)(qi)量大的(de)低(di)(di)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)泵(beng)抽氣(qi)(qi)(qi)機(ji)組，這類低(di)(di)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)抽氣(qi)(qi)(qi)機(ji)組主泵(beng)常用(yong)往復(fu)式真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)泵(beng)、油封式真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)泵(beng)、水(shui)蒸(zheng)氣(qi)(qi)(qi)放射(she)泵(beng)、水(shui)環(huan)泵(beng)、羅茨泵(beng)等(deng)(deng)。運用(yong)的(de)低(di)(di)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)抽氣(qi)(qi)(qi)機(ji)組還需根(gen)據被抽氣(qi)(qi)(qi)體清(qing)潔程度(du)、濕度(du)或(huo)其(qi)他特殊懇求，配(pei)置必要的(de)除塵器、單調罐等(deng)(deng)部件(jian)。

水蒸氣(qi)在緊縮過程中會(hui)凝結成水滴，并與泵(beng)混合(he)構成懸浮液，不只會(hui)使真空度降落(luo)，也(ye)能使泵(beng)腔與轉子生(sheng)銹(xiu)，破(po)壞密(mi)封面，使泵(beng)的極(ji)限真空度降落(luo)。為此，防止水蒸氣(qi)對機械(xie)泵(beng)的污染(ran)很重要。防止的措施有：

（1 ）選用帶有氣鎮(zhen)裝置的油封機(ji)械泵；

（2 ）裝油(you)(you)分別(bie)器、離心式(shi)分別(bie)器或(huo)油(you)(you)水(shui)分別(bie)器，將混有水(shui)的機械泵油(you)(you)中止處置，處置過的油(you)(you)再(zai)流入泵中運用；

（3 ）運用吸水性強(qiang)的單調劑(ji)；

（4 ）運(yun)用(yong)液氮冷阱，不只能有效地(di)吸附水蒸氣，同(tong)時還(huan)可以阻撓機械(xie)泵油向高真空室返流(liu)。

油擴散泵真空系統污染與防治
油(you)擴散(san)(san)泵真(zhen)(zhen)(zhen)空(kong)(kong)系(xi)統(tong)是(shi)運用最普遍(bian)的(de)(de)真(zhen)(zhen)(zhen)空(kong)(kong)系(xi)統(tong)，其獲得真(zhen)(zhen)(zhen)空(kong)(kong)度(du)范圍(wei)為1.3×10-3 ～1.3×10-5 Pa。油(you)擴散(san)(san)泵真(zhen)(zhen)(zhen)空(kong)(kong)系(xi)統(tong)構成的(de)(de)各(ge)類(lei)真(zhen)(zhen)(zhen)空(kong)(kong)裝(zhuang)置，長期運用后，常見(jian)的(de)(de)缺點是(shi)真(zhen)(zhen)(zhen)空(kong)(kong)度(du)抽不上去，或真(zhen)(zhen)(zhen)空(kong)(kong)度(du)抽不到原來的(de)(de)極(ji)限真(zhen)(zhen)(zhen)空(kong)(kong)水平(ping)。與(yu)真(zhen)(zhen)(zhen)空(kong)(kong)室內壁的(de)(de)油(you)蒸(zheng)氣污染(ran)、真(zhen)(zhen)(zhen)空(kong)(kong)工藝過程各(ge)種(zhong)污染(ran)物的(de)(de)污染(ran)有關，防止的(de)(de)辦法是(shi)：

（1 ）定期清洗(xi)真空(kong)室；

（2 ）定(ding)期對油封機械真空泵和油金屬擴散泵中止清洗。