A condenser is a piece of apparatus or equipment that can be used to condense, that is, to change the physical state of a substance from its gaseous to its liquid state; in the laboratory, it is generally used in procedures done with liquids brought into gaseous state through heating or application of vacuum (lowered pressure); often a mixture with water or other substances. Condensers can be applied at various scales, from micro-scale (very few microliters) to process-scale (many liters), using laboratory glassware and occasionally metalware that accomplishes the cooling of the vapor generated by boiling (through heating or application of vacuum).
In simplest form, a condenser can consist of a single tube of glass or metal, where the flow of outside air produces the cooling. In a further simple form, condensers consist of concentric glass tubes, with the tube through which the hot gases begin to pass running the length of the apparatus. The second tube defines an outer chamber through which air, water, or other cooling fluids can pass to reduce the temperature of the gasses to afford the condensation; hence, the outer tube (or, as designs become more complex, outer cooling chamber) has an inlet and an outlet to allow the cooling fluid to enter and exit.
A variant of the Liebig condenser having a more slender design, with cone and socket. The fused-on narrower coolant jacket may render more efficient cooling with respect to coolant consumption.
The Allihn condenser or “bulb condenser” or simply “reflux condenser” is named after Felix Richard Allihn. The Allihn condenser consists of a long glass tube with a water jacket. A series of bulbs on the tube increases the surface area upon which the vapor constituents may condense. Ideally suited for laboratory-scale refluxing.
A Davies condenser, also known as a double surface condenser, is similar to the Liebig condenser, but with three concentric glass tubes instead of two. The coolant circulates in both the outer jacket and the central tube. This increases the cooling surface, so that the condenser can be shorter than an equivalent Liebig condenser.
A Graham condenser (also Grahams or Inland Revenue condenser) has a coolant-jacketed spiral coil running the length of the condenser serving as the vapour/condensate path. This is not to be confused with the “coil condenser”. The coiled condenser tubes inside will provide more surface area for cooling and for this reason it is most favorable to use but the drawback of this condenser is that as the vapors get condensed, it tends to move them up in the tube to evaporate which will also lead to the flooding of solution mixture.
A coil condenser is essentially a “Graham condenser” with an inverted coolant/vapor configuration. It has a spiral coil running the length of the condenser through which coolant flows, and this coolant coil is jacketed by the vapor/condensate path.
A Dimroth condenser, named after Otto Dimroth, is somewhat similar to the “coil condenser”; it has an internal double spiral through which coolant flows such that the coolant inlet and outlet are both at the top. The vapors travel through the jacket from bottom to top. Dimroth condensers are more effective than conventional coil condensers. They are often found in rotary evaporators.
A spiral condenser has a spiral condensing tube with both inlet and outlet connections at top, on same side. See Dimroth condenser.
A Friedrichs condenser (sometimes incorrectly referred to as “Friedrich’s” condenser), a spiraled finger condenser, was invented by Fritz Walter Paul Friedrichs, who published a design for this type of condenser in 1912. It consists of a large, spiraled internal cold finger-type capillary tube disposed within a wide cylindrical housing. Coolant flows through the internal cold finger; accordingly, vapors rising up through the housing must pass along the spiraled path.