Product line-up

HOME > Product line-up > Evaporators > What is a Rotary Evaporator? > What is a Rotary Evaporator?

70 years of Heritage and Innovation



Introduction: Rotary Evaporators
Rotary evaporators have become an indispensable tool in chemical, engineering, and biological research. They are among the most essential concentration devices used in laboratories and testing facilities for a wide range of applications, including concentration, fractional distillation, separation, and distillation.

EYELA’s rotary evaporators are designed to significantly reduce concentration and distillation times while enabling high-precision fractionation and separation. Furthermore, our commitment to safety-driven design has earned us deep trust across countless research and manufacturing sites worldwide.

Structure of a Rotary Evaporator

Components and Functions

Reduces the pressure within the glass components to lower the boiling point of the solvent. For example, water boils at approximately 87°C at the summit of Mt. Fuji (3,776m, approx. 630hPa).

The liquid heated within the rotating sample flask flows into the condenser as vapor.

As cooling water flows through the condenser coils, the vapor is cooled, liquefied, and collected in the receiving flask.



  • The difference (△T) between the sample’s boiling point and the cooling water temperature must be at least 15 to 20°C. (The boiling point varies depending on the vacuum level. A minimum △T of 10°C is required.)
  • Maintain a temperature difference (△t) of 10 to 40°C between the heating bath and the sample’s boiling point.
    (A minimum △t of at least 10°C is required.) By increasing △t (the difference between the boiling point and cooling water) and decreasing △t (the difference between the heating bath and the boiling point), the evaporation rate decreases, but the recovery rate increases.

What a Rotary Evaporator Can Do

Concentration

To concentrate the components in a liquid
・Pre-treatment for analysis
・Removal of the extraction solvent
・Drying and dehydration of the sample

Fractionation / Separation

To separate volatile and non-volatile components
・Separation of mixed solvents

Distillation

To recover the condensed fraction based on the varying volatilities of the components
・Solvent purification

Frequently Asked Questions (FAQ)

Rotating the flask creates a thin film of solution on the inner wall, increasing the surface area. Additionally, a film of warm water forms on the outside, enhancing heat transfer into the flask. The resulting agitation also prevents bumping (sudden boiling).

They gradually wear out and fail to maintain a vacuum, so periodic replacement is necessary. The vacuum seal wears out first, but its lifespan varies significantly depending on the samples used and the rotation speed. Therefore, regularly perform a vacuum check with an empty flask and a vacuum gauge to verify the ultimate pressure. While the rotary joint can be used for a long period, grooves will eventually form where it makes contact with the vacuum seal. Once these surfaces become uneven, it is time for replacement.

Click here for Frequently Asked Questions (FAQ)

Rotary Evaporator Configuration

We can meet a wide range of needs by adding various accessories and options to the basic configuration.


Click here for more details on each product
Rotary Evaporators
N-1300 Series Selection Guide
Low Temperature Circulators (Chillers)
Vacuum Pumps
Vacuum Pump Controller
Solvent Recovery Units
Cold Traps

System Examples of Rotary Evaporator

The following are just a few examples; our catalog introduces a wide range of system configurations tailored to various needs.
We also offer a variety of glass components with a special coating (EYELA COAT®) that minimizes the scattering of glass fragments in the event of breakage.

Environmental Regulation Compliance System
Equipped with numerous safety features
Product nameModelCat. No.QTY
Rotary evaporatorN-1300V-WS2753401
Low temperature circulatorCCA-1112A2684501
Diaphragm vacuum pumpNVP-10002618001
Solvent recovery unitDPE-11502711801
NVC communication cordCOM-1M2694603
NVC communication cordCOM-2M2694701
Branch box for NVC communicationF-BOX2696201
Anti-condensation cover2707401
Cooling hose set 2m 9mm OD1127003
Vacuum hose 6 x 15mm1191701
Nybrine® 4kgZ-12635001
Anti-condensation nozzle cover2821301
Total System Power Capacity 20.6A, 3 outlets required

Click here for other standard concentration system examples.

Maintenance Methods

Pre-use inspections and periodic maintenance of rotary evaporators are essential for maintaining performance and extending service life. Below are the specific inspection and maintenance methods.

1. Pre-use Check

Before use, inspect all glass components for any damage and ensure the EYELA Clip, which secures the sample flask to the rotary joint, is not cracked. Confirm that the water or oil level in the bath is appropriate, and that the vacuum and cooling water hoses are correctly connected and free of cracks. Check for any liquid leaks from the cooling water nozzle connections.

2. Cleaning of each part

Wipe the glass components and other parts with a soft cloth, and apply a small amount of vacuum grease to the joints. (Consider the possibility of vacuum grease contamination.) After use, reapply vacuum grease to prevent seizing.

3. Dryving unit

Turn on the power switch and press the RUN/STOP key to confirm that the rotation driving unit rotates smoothly from low to high speeds without any unusual noise or eccentricity. Ensure the jack lifts and lowers smoothly and that there is no interference. Just before starting the experiment, confirm that the rotating sample flask is properly immersed in the heating bath and that the bath fluid will not overflow due to thermal expansion of the liquid level.

4. Cleaning after use

After use, clean the surface of the equipment with a soft cloth to remove any remaining oil or solvent residue. Please clean the glass vessels in accordance with your facility’s glassware cleaning protocols.

5. Checking for vacuum leaks

Disconnect the joints, check for dirt, and wipe it away with a soft cloth before applying a small amount of vacuum grease. Periodically check for vacuum leaks while the rotor is rotating. If parts are seized, use heat-resistant gloves and a hot gun (a hairdryer can also be used) to warm the ground joints and melt the hardened solvent or grease to facilitate removal.

6. Protection of electrical components

Take care to keep moisture away from electrical components; in particular, moisture at wiring junctions is strictly prohibited. Since cooling water piping is prone to condensation, ensure there is sufficient distance between the piping and the electrical wiring.

7. Use of genuine parts

Please use genuine parts. Mixing and using components from other manufacturers may cause fatal damage to the equipment.

8. Periodic inspection and repair

Please ensure that you perform periodic inspections on a regular basis.

Safety

Rotary evaporators are devices used for the efficient evaporation, separation, and concentration of solvents in chemical experiments, but several precautions are necessary to ensure safety. The use of personal protective equipment (PPE) is fundamental, and the use of safety glasses is specifically recommended. Furthermore, due to the risks of burns or implosions, it is important to manage the temperatures of the cooling water and the bath, control the vacuum levels, and avoid contact with the rotating sample flask. Additionally, attention must be paid to the volatility of hazardous solvents, and proper ventilation is required.

Safety regarding rotary evaporators is critically important in laboratory work. The following details the key elements related to rotary evaporator safety.

1. Wear of Personal Protective Equipment

When operating the equipment, it is recommended to wear safety glasses or goggles, a lab coat or apron, chemical-resistant gloves, and closed-toe shoes. These measures protect the body from chemical splashes and vapors.

2. Proper Ventilation

To reduce the risk of inhaling volatile solvent vapors, it is essential to use an exhaust hood to capture and discharge harmful vapors. In addition to ensuring overall laboratory ventilation, it is highly recommended to install the equipment inside a fume hood.

3. Equipment Inspection and Maintenance

Periodically inspect the condition of glassware and seals, checking for any cracks or wear. Promptly replace damaged parts and maintain the vacuum pump to prevent equipment failure.

4. Safe Operating Procedures

Confirm that all components are functioning normally at startup, and monitor the temperature and level of the water or oil in the bath. Adjust the pressure gradually to prevent sudden evaporation caused by rapid pressure changes (use vacuum controllers, trap bulbs, or bumping prevention device (safety cap)).

5. Emergency Preparedness

Conduct regular safety training to ensure that employees are familiar with emergency response procedures. It is also important to place emergency equipment, such as fire extinguishers and spill kits, in readily accessible locations.

Adhering to these guidelines enables the safe use of rotary evaporators and significantly reduces the risk of accidents in the laboratory.