短語(yǔ)詞組短語(yǔ)positive -displacement seawater fresh water pump 容積式海水泵double -stage positive displacement vacuum pump 雙級(jí)結(jié)搆容積式真空泵positive displacement oil -sealed liquor pump 油封式正位移式打液泵diaphragm -type positive displacement metering pump 隔膜型正排量計(jì)量泵 返回 positive-displacement pump