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Laboratory Condensers Information

Laboratory condensers are used in distillation and reflux processes and comprise of glassware. The apparatus assists in cooling liquids and condensing vapors or gasses from solutions. Their use allows hot solvent vapors from a heated liquid to cool and drip back, resulting in reduced solvent loss and lengthening the time to heat the solution. Standard tools do not involve electrical components.


laboratory condensers specification guideThe inner glass tubes contain ends equipped with graduated glass joints or grounded joints to fit other glassware. When reflux occurs, the upper end is kept open to the air or vented via a bubbler or drying tube, preventing water or oxygen from entering. The ground glass joints support connections with the apparatus. Select products rely on threaded fittings for water jackets connecting hoses for circulating the cooling fluid.


Types of Laboratory Condensers


Simple condensers consist of single tubes where vapor heat conducts to the air-cooled glass wall of the tube. Similar air versions support condensation of boiling liquids at high temperatures.


Numerous air- and fluid-cooled options are available and include:


Vigreux columns feature downward facing finger indentations on the inside wall that provide an increased surface area relative to the unit length of the instrument. Use of such columns adds equilibrium stages necessary for fractional distillation. Their design incorporates outer glass cylinders or open-air access for fluid circulation. If added insulation is desired, it is possible to equip the devices with an outer vacuum jacket.


Snyder columns are effective for fractional distillations. They are air-cooled and comprise a single glass tube featuring circular indentations located in the cylinder walls. Each indentation holds a hollow teardrop-shaped  glass stopper. Additional Vigreux-type indentations inhibit the rise of the glass stopper by vapor flow. When positioned at the resting point, the element acts as a seal. The glass stoppers act as check valves, improving vapor-condensate mixing by closing and opening in response to the flow. Snyder columns are engaged in separating low boiling solutions from higher boiling extract components.


Widmer columns are air models invented by Gustav Widmer in the early 1920s. It is a complex model with Goldetz-type tubes, and a Dufton glass rod with a wound spiral located at the center of the device.


Liebig condensers (shown at right) are simple circulating fluid structures. It includes a straight, inner tube with a corresponding outer tube surrounding it. The outer tube possesses ports permitting the inflow and outflow of substances. The two tubes are sealed at both ends. The elevated heat capacity of the circulating water helps maintain constant temperature within the component. The construction fills with materials to increase its surface area and aid in managing equilibrium stages present in the distillation column.


West condensers are a variant of the Liebig version. It presents a thinner assembly using cone and socket. The coolant jacket is fused on and narrower leading, to improved coolant consumption.


Allihn condensers, also known as bulb condensers, consist of long glass tubes with water jackets. The tubes include series of bulbs increasing the surface area where the vapor constituents condense. Their configuration is well suited for laboratory reflux applications.


Davies condensers or double surface condensers, are similar to Liebig types but involve three concentric glass tubes. Coolant circulates both in the outer jacket and in the central tube. This extends the cooling surface, allowing for shorter models than the Liebig version.


Graham condensers feature a spiral coil equipped with a coolant jacket running along the length of the unit. This serves as a path for the vapor and condensates.


Coil condensers are differentiated from the Graham configuration by an inverted coolant/vapor configuration. They possess spiral coils along their length, allowing for the flow of substances.


Jacketed coil condensers present a jacketed coolant coil for the vapor/condensate path.


Dimroth condensers involve internal double spirals that facilitate coolant flow with both inlet and outlet at the top of the device. Vapors pass through the jacket via a bottom to top path. These components offer greater effectiveness than traditional coil systems. They are employed in rotary evaporators.


Friedrichs condensers are spiraled finger instruments invented in 1912. It features a sizable internal "cold finger" capillary tube with spiraled shape in a cylindrical housing.




Condensers serve in laboratory procedures involving:


  • Organic liquids
  • Inorganic chemistry
  • Separation of chemical components
  • Simple evaporation



An array of considerations applies to the process of selecting laboratory equipment. These include:


Ground glass joints: Many instruments feature two ground glass joints allowing for easier interaction with other items. They eliminate the need for rubber stoppers and the potential corrosion such parts experience. Units with ground glass joints are more expensive than those without them.


Type Considerations


  • Liebig structures are ideal when handling substances with boiling points above 100º C, but not for volatile solvents. They function in both distillations and refluxes.
  • Graham apparatus works best for distillations when the apparatus remains in a vertical position, with liquid nitrogen acting as a coolant. They are difficult to use with refluxes and are subject to clogging.
  • Coil condensers offer operation and avoid the difficulties experienced by Graham substitutes in regard to clogging.
  • Allihn implements are deployed with refluxes. Condensations are trapped in the bulbs when distilling.
  • Dimroth options support efficient distillations and refluxes.
  • Davies versions sustain condensation of substances from a broad range of boiling points.
  • A jacketed coil condenser's coil tube performs better than the straight tube in Davies condensers.
  • Friedrichs products are suitable for distillations as well as refluxes.

Image credits:

SCHOTT North America—Glass Tubing


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