往返: go there and back; come and ...互换: interchange; counterchange; ...提纯器: purifier往近互换提纯器: reciprocating refiner往返互换的加热器: reciprocating heater往返互换加热器: reciprocating heater往返互换式加热器: reciprocating heater提纯器: cleanser; deionizer; purer; purifier; purifying agent; refiner; treater氮气提纯器: nitrogen purifier黄金提纯器: gold sublimator净化器;提纯器: purifier区域提纯器: zone refiner; zoner提纯器,纯化器: purifier筒形提纯器: drum refiner氧气提纯器: osublimator粘土提纯器: clay purifier区域空段提纯器: zone-void refiner区域输运提纯器: zone-transport refiner三重回收提纯器: triple-withdrawal refiner正交流动区域提纯器: cross-flow zone refiner提纯: purification; purify; refine; refinement◇提纯复壮 purification and rejuvenation; 提纯剂 purificant; 提纯器 purifier; 提纯塔 purifying column [tower]; 提纯油 good oil往返: 1.(来回) go there and back; come and go; arrive and depart 往返要四个小时。it takes four hours to go there and back.2.(反复) journey to and fro 往返于京津之间 travel to and fro between beijing and tianjin; 往返奔波 ceaselessly come and go; 往返航程 round voyage; 往返贸易 countertrade; 往返时间 round-trip time; 往返运费 freight out and home再纯器: repurifier互换: interchange; counterchange; mutual exchange; double replacement; exchange; interconversion; reciprocate; transposition; permutation◇互换货币协定 swap agreement交换提单: switch bill of lading