Rotary Evaporators

What is a Rotary Evaporator?

Rotary evaporators are essential tools used for evaporation, distillation, and solvent recovery. This process is commonly utilized to separate solvents with low boiling points, such as n-hexane or ethanol, from compounds with higher boiling points. By combining vacuum, heat, and rotation, a gentle and efficient method of distillation is created. Rotary evaporators provide optimal evaporation, with minimal heat and oxidative stress, because of this they are extremely popular in process chemistry as well as in botanical extraction.

UL and CSA Certification Now Standard!

The new Ai SolventVap rotary evaporator series are now UL/CSA compliant. This certification is required by many municipalities, it also provides a higher standard of equipment safety and conformity. In addition to new orders coming standard with UL/CSA, we can also provide retro-certification services for any Ai SolventVap (5L or larger) that is already in the field.

Across International is proud to offer these important certifications at a fraction of the cost as compared to other brands. Contact us today for a quote!

 Key features

Popular uses in botanical extraction

Solvent recovery to create crude oil – After an ethanol extraction, or winterization stage, rotary evaporators are used to distill off the solvent. This process allows for the safe and efficient separation of solvent and crude oil, the solvent is evaporated, re-condensed and collected, while the target oil remains in the evaporative flask.

Distillation for solvent recycling – When a solvent has been used several times in an extraction process, or it has been exposed to water and contaminates, it loses its effectiveness and cannot be re-used as is. At this point the solvent is thrown away and replaced, often a costly choice, or it can be distilled for re-use. Rotary evaporators allow for an efficient method to clean and recycle solvents.

Distillation for Hydrosol – By loading the evaporative flask with plant material and water, then distilling the water, a solution known as hydrosol is created. This can be done with various plants, flowers, and fruits in order to create water-based solutions that carry small amounts of essential oils, terpenes, and various compounds.

Solvent recovery in re-crystallization – During the re-crystallization process of CBDA, and various cannabinoids, a stage of distillation can often be utilized. There are times when rotary evaporators can assist with drying crystals, while removing the final amounts of solvent. There are other times when the rotary evaporator is essential for cleaning solvents as well as separating mother liquors.

Key components

The rotary evaporator’s most essential component is the evaporating flask, this rotating spherical flask is where the heating and distillation begins, as well as where the solution, and end products, are held. When the rotating spherical flask is connected to the knuckle and motor, it is then lowered into a heating bath (or the bath is raised to the rotating flask) where it will spin as it is heated by the bath it is now half submerged in. The heating bath is essential for efficient evaporation as it allows for more rapid boiling of the solution. Additionally, the rotation is crucial as it agitates the solution, and also draws it up the sides of the rotating flask, creating more surface area for the distillation process to begin. Heat and rotation are integral to the correct operation of a rotary evaporator.

The rotating spherical flask is crucial, but there are many other glass components as well as locking nuts and seals that allow for the entire system to be built and placed under vacuum. The rotating flask is connected to the motor with a series of O-rings and locking nuts, this allows for it to spin and remain under vacuum. In order for vapor and liquids to pass through the rotating flask, two components run through the center of the flask neck, but do not rotate. The vapor duct, or vapor tube, is a larger diameter glass tube and is essential for operation. Through the vapor duct sits the material feed tube, when under vacuum the material feed tube can be used to draw in solution allowing for smooth and easy filling of the rotating flask.

On the back side of the motor, that is connected to the evaporator flask, there is an essential connection. Generally this glass hub has 3 or 4 ports, and would be referred to as a 3-neck flask or a 4-neck flask accordingly. This piece of glass connects the condenser coils to the motor assembly, essentially tying it into the rotating flask, it also holds the end of the material feed tube, which is used to draw in material as well as vent to atmosphere. Without this 4-neck flask the rotary could not function.

Equally important as the rotating flask, but on the opposite end, is the condenser and collection flask. The condensers of a rotary evaporator allow for the solvents and solutions that were boiled off to be re-condensed and collected safely. Generally, the condensers are a glass shell, with a glass coil that runs in the center. The center glass coil is kept cold by means of a chiller, or water source, continually circulating cold fluid through the coil. The hot vapors traveling from the rotating flask meet the condenser coil, begin to cool down, and condense into a liquid once more. When all these components are connected and set, vacuum can be pulled on the system, and the rotary is functional.

The Across International Advantage

Ai SolventVap rotary evaporators provide high distillation rates at an affordable price. All models from 2L to 50L can be UL, CSA, and CE certified, and are backed by award winning customer support. We understand that down time can be devastating, that is why we offer next day shipping on parts, or in-store pick up from our NJ and NV locations. For reliable and efficient distillation look no further.