What is a Rotary Evaporator?

What is a Rotary Evaporator?

  A rotary evaporator, known as “rotavap” as well, refers to a kind of equipment for solvent evaporation under reduced pressure, which is composed of a vacuum system, a heated water or oil bath, a condenser and a motor that rotates the evaporation flask. As its name suggests, what is special is that the evaporation flask can rotate.

  A rotary evaporator can be used to recover and evaporate organic solvents. A motor is the part to drive the evaporation flask to rotate. Since the evaporation flask is continuously rotating, materials can be added without stopping the equipment. At the same time, due to continuous rotation, the liquid is attached to the wall of the flask, forming a liquid film, which increases the evaporation area and accelerates the evaporation rate.

rotary evaporator
rotary evaporator

What is the Principle of a Rotary Evaporator?

  The evaporation flask is an eggplant-shaped or round-bottomed flask with a standard grinding port. It is connected to a pressure-reducing pump through a highly refluxing serpentine condenser tube. The other opening of the reflux condenser tube is connected to a receiving flask with a grinding port. There is a three-way piston between the condenser tube and the vacuum pump. When the system is connected to the atmosphere, the evaporation flask and the liquid flask can be removed while the solvent is transferred. During the working process of rotary evaporator, the pressure should be reduced firstly, and then the motor should be turned to rotate the distillation flask. In the end, it should be shut down and then vented to the atmosphere to prevent the distillation flask from falling off during rotation.

What are Applications of a Rotary Evaporator?

A rotary evaporator is mainly used for the process of evaporation, concentration, crystallization, drying, separation, and solvent recovery, and especially used for the continuous distillation of large amounts of volatile solvents under reduced pressure. With so many application purposes, there is no doubt that a rotary evaporator can be applied in many areas. For example, it can be used in the small and pilot experiments and production in the biological, pharmaceutical, chemical fields and even food-making industries.

rotary evaporator
rotary evaporator

How to Use a Rotary Evaporator?

  1. Before turning on the rotary evaporator: firstly turn the speed control knob to the lowest left, press the electric copy source switch indicator light, then slowly turn it to the right to the desired speed. Generally, large evaporating bottles use low and medium speeds and high viscosity.
  2. During the working process of rotary evaporator, firstly reduce the pressure, then start the motor to rotate the distillation flask. Finally, stop the motor first, and then open the atmosphere to prevent the distillation flask from falling off.
  3. Rotary evaporator height adjustment: manual lift, turn the handwheel on the column, turn up and down in turn; electric lift, touch the up button to raise the host, touch the down button to lower the host.
  4. There are two external connectors on the condenser for cooling water, one is connected to the water, and the other is connected to the outlet. Generally, the tap water is connected. The lower the temperature of the condensate, the better the effect will be. The upper port is provided with a vacuum connector, a vacuum connector and a vacuum pump sleeve.

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