冷凝管是用作促成冷凝作用的实验室设备，通常由一里一外两条玻璃管组成，其中较小的玻璃管贯穿较大的玻璃管。

冷凝管的内管两端有驳口，可连接实验设备的其他设备，让较热的气体或液体流经内管而冷凝。外管则通常在两旁有一上一下的开口，接驳运载冷却物质 (如水) 的塑胶管。使用时，外管的下开口通常接驳到水龙头，因为水在冷凝管中会遇热而自动流往上方，达至较大的冷却功效。

回流设备和蒸馏是两个经常用到冷凝管的实验设备。

A condenser is an apparatus or item of equipment used to condense (change the physical state of a substance from its gaseous to its liquid state). In the laboratory, condensers are generally used in procedures done with organic liquids brought into gaseous state through heating with or without lowering the pressure (applying vacuum)—though applications in inorganic and other chemistry areas exist. While condensers can be applied at various scales, in the research, training, or discovery laboratory, one most often uses glassware designed to pass a vapor flow over an adjacent cooled chamber. In simplest form, such a condenser consists of a single glass tube with outside air providing cooling. A further simple form, the Liebig-type of condenser, involves concentric glass tubes, an inner one through which the hot gases pass, and an outer, "ported" chamber through which a cooling fluid passes, to reduce the gas temperature in the inner, to afford the condensation.