20L Best Value Rotary Evaporator

Category: Tags: , ,


Weight 250 lbs


Rotary evaporator’s are used in laboratories to gently remove and recover solvents from a given mixture via evaporation. Rotary evaporation is done by heating a mixture while lowering the atmospheric pressure using a vacuum system. This lowers the boiling point of the solvent forcing a phase change from liquid to vapor. The vapor is then pulled into the path of the condenser by the vacuum system where it is re-condesened back into a liquid and falls into a seperate collection flask.

The following example illustrates the process: A mixture containing extract and ethanol must be seperated before further distillation can occur. The mixture is heated to approximately 110F inside the rotary evaporator while simultaneously pulling a vacuum. This causes the pressure inside the roto to drop into a vacuum effectively dropping the boiling point of the ethanol to a level where it switches phases from liquid to vapor. As the evaporation flask turns, the mixture creates a thin film on the interior of the flask forcing the evaporation to happen at a quicker rate. The ethanol vapor is pulled into the cold condenser where the vapor is trapped and turns back into liquid. The liquid then drops into the collection flask and can be re-used for further processing. The original extract is then left in the rotary flask for futher distillation.

To run a rotary evaporator most efficiently, you will need a chiller capable of keeping it’s temperature under the given heat load, a chemical resistant diaphragm vacuum pump, and an cold trap to catch any vapors that pass through the condenser. BVV rotary evaporator’s are simple, cost-effective, and durable machines that allow you to recover your solvents for use again and again. Don’t let evaporation be the bottleneck in your processing! 

The following table illustrates example solvnets and how their chemical composition changes by manipulating the vapor pressure:

Vapor Pressure

Unit Specifications:

  • Glass Material: GG-17 High Borosilicate Glass
  • Shelf Material: Aluminum Alloy
  • Pot Material: Stainless Steel, Fully sealing and heating
  • Rotary Bottle Capacity: 20L
  • Collection Bottle Capacity: 5L
  • Rotary Power: 120w (110v/60hz)
  • Rotary Speed: 0-180RPM
  • Heating Power: 5KW (208v/3Φ/60hz)
  • Bath Temperature Control Range: 0-99c
  • Digital Temperature Control
  • Temperature Control Accuracy: +/-1C
  • Lifting Mechanism: Electric
  • Dimensions Assembled (LxWxH in.):  25x52x80
  • Weight: 130 LBS

“Continuous Feed” Operating Procedure:

This procedure is the most efficient way to run a rotovap. It will give you the fastest speeds, with minimal heat load to the chiller. This procedure is meant to be a basic starting point for anyone new to using rotovaps. It assumes you are evaporating an ethanol solution for recovery and reuse of the ethanol. Once you have mastered this procedure, you can begin adjusting the parameters to suit your specific needs. 

  • Clean and assemble unit. Make sure all pieces are cleaned and sterilized using an alcohol solution.
  • Connect chiller to condenser and set to 0C (32F). Always fill a rotovap condenser from the top down (chiller output to top of condenser, chiller input to bottom of condenser).
  • Connect vacuum pump to cold trap and connect cold trap to vacuum port on rotovap.
  • Turn on heat bath and set to 40C (113F).
  • Once heat bath, chiller and cold trap have reached desired temperatures, turn on rotovap motor and set speed to approximately 100 RPM (does not have to be precise).
  • Start vacuum pump and allow vacuum to pull down for a few minutes before injection.
  • Once vacuum has been pulled to a sufficient level (does not have to be precise but should be below 100 Torr), using the injection valve, very slowly inject approximately 500 mL of solution into evaporating flask and then close the valve. Allow this small amount to begin evaporating. You may see the chiller begin to rise in temperature, this is called “priming” the rotovap.
  • Once the temperature stops rising or all liquid is almost completely evaporated, open the injection valve again very slowly so that a small amount of liquid begins to enter the evaporating flask. Do not close injection valve this time but continue to allow solution to enter the evaporating flask. 
  • At this point you must try to match the input speed to the output speed. What this means is that you should be injecting the same amount of liquid into the rotovap that is equal to the amount of liquid dripping from the condenser into the receiving flask. You will know that the input speed and output speed are matched because the chiller will remain at a stable temperature. If the chiller begins to rise, then you are injecting too much liquid. Dial back the valve until the chiller stabilizes.
  • Once everything is stabilized, you may walk away from the rotovap if necessary. Check every so often to make sure temperatures remain stable and evaporation continues efficiently. 

Does not include: Chiller, Vacuum System, Cold Trap 

Requires Assembly

***Note: All units are inspected for broken glass or parts before unit is shipped. If unit arrives damaged or glass is broken (this does not include minor imperfections or scuffs in glassware), Customer MUST contact Best Value Vacs within 3 days of delivery to file a claim and receive a replacement part. If customer DOES NOT contact Best Value Vacs within 3 days of delivery responsibility for replacement parts falls on the customer and they must pay for replacement pieces.***

***Note: This item will ship by freight only.***

***Disclaimer: This unit is intended for LEGAL purposes only, to be used in accordance with local laws and ordinances. Use only in WELL VENTILATED AREAS!***

Weight 250 lbs