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Everything You Want to Know About Rotary Evaporator

Views: 348     Author: Site Editor     Publish Time: 2023-07-28      Origin: Site

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What Is a Rotary Evaporator?

A rotary evaporator, also known as a rotavap or rotovap, is a common laboratory equipment used to remove solvent from the solution through the process of evaporation.

Rotary evaporators are primarily used in chemical labs for concentration, crystallization, separation, and solvent recovery. They are also used in many fields for their versatility, including pharmaceutical, chemical, and biotechnology industries.

The Main Parts of a Rotary Evaporator

The main components of a rotary evaporator are:


① Evaporation Flask

The evaporation flask is to contain the sample being processed and it typically has a large surface area and is driven by a motor to rotate for efficient evaporation. The rotating flask ensures homogenous heating of the sample, hastening the evaporation.

② Rotary Motor

The electric motor plays a crucial role in rotating the evaporation flask at a continuous and constant speed. Rotation not only greatly enlarges the active surface inside the flask, but also reduces bumping and foaming during heating.

③ Heating Bath

The mainly used heating bath is a water bath or an oil bath depending on the boiling points of different solutions. It provides a source of heat to the evaporation flask, helps regulate the temperature of the sample and maintains a stable pressure inside the evaporator.

④ Vacuum System

The pressure inside the rotary evaporator is decreased by using a vacuum pump, which lowers the solvent's boiling point and hastens the evaporation process.

⑤ Condenser

It is mainly found in a long glass tube and its function is to cool and condense the vaporized solvent produced by the sample that is heated in the evaporation flask.

⑥ Receiving Flask

Beneath the condenser is a receiving flask that is used to collect the condensed solvent.

How Does the Rotary Evaporator Work?

A rotary evaporator removing solvents from samples is based on the principle of lowering the boiling point of solvents under reduced pressure. The evaporation flask rotates at a constant speed, forcing the materials to form a large area of uniform thin film on the inner surface of the rotating flask.

The evaporation flask is heated evenly in a water or oil bath, and materials, with a lower boiling point, is evaporated quickly under the vacuum condition. The vapors are then condensed by a glass condenser and collected in a receiving flask.

How Does Solvent Evaporate in the Rotary Evaporator?

A rotary evaporator is essentially a distillation device that operates under vacuum conditions to reduce the boiling point of solvents and separate them from other components.

The mixture to be processed in an evaporation flask is placed in the water bath to heat. A motor drives the flask to rotate at a constant speed, which increases the liquid's surface area and thus improve the rate of evaporation. The mixture is heating while the system is partially evacuated (by a vacuum pump). The reduced pressure in the apparatus leads to lower the boiling point of the solvent. As the solvent boils and evaporates, it turns into vapor, which travels through a condenser where it cools and condenses back into liquid form. The condensed solvent is then collected in a receiving flask, leaving behind the solid or concentrated liquid sample.

As the solvent evaporates, the remaining liquid becomes more concentrated, which might cause bumping or splashing. To avoid this, a bump trap is used between the vapor tube and evaporation flask to prevent contents of the flask from being drawn into the condenser in the event of bumping.

Advantages of the Rotary Evaporator

Rotary evaporators are commonly used for the separation and concentration of liquids in a variety of fields. Four E's Scientific offers the best choice for trustworthy performance and superior quality rotary evaporator. Our rotary evaporator is especially designed for chemical, pharmaceutical, biotechnology industries and R&D labs to separate and concentrate samples. Below are some top-notch features making it a reliable choice in the marketplace.

Easy to Use

Four E's Scientific Rotary Evaporators boast the user-friendly design and intuitive interface. It comes with a large LED display and touch keys, along with an adjustable knob that helps you easily set the rotation speed, heating temperature, operation time, and cycle times, etc.

Precise temperature control

Adopting proportional integral derivative(PID) temperature controller, Four E's Scientific Rotary Evaporator provides accurate and precise temperature regulation during operation, which effectively avoids samples deterioration or disintegration.

Efficient Separation

It also features high evaporation rate by increasing the sample’s surface area and lowering its boiling temperature to facilitate the solvent to be effectively separated in a short time. The brushless DC motor provides efficient and gentle evaporation, so that heat transmission in the heating bath as well as inside the flask is greatly improved by rotating the evaporation flask.

Long service life

The sealing system utilizes high elastic graphite filled PTFE seal and compression spring to achieve excellent sealing, which is resistant to high temperature, corrosion, and abrasion.


Looking to upgrade your rotary evaporator? Trust in Four E's Scientific to perform a high efficiency evaporation and enjoy easy and safe workflow in your labs. Get one Four E's rotary evaporator today and make your work easier!

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