A rotary evaporator (or rotavap/rotovap) is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation.

A rotary evaporator is a piece of machinery or equipment used in the creation of some cannabis concentrates. A rotary evaporator evaporates and recovers pricey ethanol from ethanol-extracted concentrates.

Rotary evaporators are one of the key steps in creating butane hash oil (BHO) and other cannabis concentrates. Using the rotary evaporator helps effectively concentrate the oil to a concentration of 15 to 40 per cent. It also purges the solvents from the finished product and recovers them, making the oil exceptionally pure.

Rotary evaporation is the process of reducing the volume of a solvent by distributing it as a thin film across the interior of a vessel at elevated temperature and reduced pressure. This promotes the rapid removal of excess solvent from less volatile samples. Most rotary evaporators have four major components: heat bath, rotor, condenser, and solvent trap. Additionally an aspirator or vacuum pump needs to be attached, as well as a bump trap and round bottom flask containing the sample to be concentrated.


Working principle of the rotary evaporator

Rotary evaporator is a kind of evaporation instrument, which is widely used in the chemical laboratory. It is suitable for reflux operation, rapid evaporation of a large number of solvents, concentration of trace components, and reaction processes that require stirring, especially for continuous distillation of large amounts of volatile solvents under reduced pressure.

Rotary evaporator, which is also called rotovap, is mainly a laboratory common equipment consisting of: motor, distillation flask, heating pot, condenser tube and other parts.

1. The evaporation flask is an eggplant-shaped or round-bottomed flask with a standard grinding mouth connection. The reflux serpentine condenser tube is connected to a pressure reducing pump.

2. There is a three-way piston between the condenser tube and the pressure reducing pump. When the system is connected with the atmosphere, the evaporation flask can be removed. What’s more, the solvent will be transferred. When the system is connected to the pressure reducing pump, the system should be under reduce pressure.

3. During the working process, the pressure should be reduced firstly, and then the motor should be turned to rotate the evaporation flask. In the end, the machine should be stopped and ventilated to prevent the distillation flask from falling off during rotation.

As the heat source for evaporation, a constant temperature water tank should be often provided. Through electronic control, the flask is rotated at a constant speed at the most suitable speed to increase the evaporation area. The evaporation flask was brought to a negative pressure state by a vacuum pump.

In short ,the principle of the rotary evaporator is electronically controlling the distillation flask to rotate at a constant speed at the optimum speed to increase the evaporation area.At the same time through the vacuum pump to make the evaporation flask in the state of negative pressure. The evaporation flask was heated in a water bath while rotating at a constant temperature, and the solution in the bottle was subjected to heat diffusion evaporation in a rotating flask under a negative pressure.The evaporation system can be sealed to a pressure of 400 to 600 mm Hg; the solvent in the distillation flask can be heated by a heating bath to heat up to the boiling point of the solvent; and the rotation can be carried out at a speed of 50 to 160 rpm to form a solvent film. Increase the evaporation area. In addition, the hot vapor can be quickly liquefied by the high efficiency cooler to accelerate the evaporation rate. The above is the introduction of the working principle of the rotary evaporator.

How to use a rotary evaporator?

Even though the rotary evaporator (or rotovap for short) looks pretty complicated, it’s really pretty simple. The purpose of the rotovap is to remove low boiling organic chemicals, usually solvents, from a mixture of compounds. The rotary evaporator is the method of choice for solvent removal in the modern organic laboratory. The solvents or low boiling compounds are removed by a simple distillation. The rotovap is designed to be operated under a vacuum (to lower a compound’s boiling point) while heating the sample at the same time. A cold finger is used to condense the vapors to a liquid, which are trapped in a separate flask.

Structure of Rotary Evaporator

Important Features of the Rotovap

1) The vacuum pump is the source of reduced pressure in the system.

2) Spin speed and bath temperature control knobs.

3) Water bath.

4) Bump guard.

5)Cold finger. (Please do not use the rotovap if the finger is not cold. There should be excess solid dry ice in the finger.)

6)Vacuum release valve.

To use the rotovap, follow these simple steps:

1. Connect the hose to the condenser tap,Connect the vacuum pump with the vacuum rubber hose for vacuuming.

2. Fill the tank with water (preferably pure water),If you use tap water, leave it for a day or two before using .

3. The method of adjusting the host Angle:Simply loosen the main unit and the column to connect the screw to the main unit and tilt it between 0 and 45 degrees.

4. Switch on the condensate water, switch on the power supply, connect the evaporator with the host machine (do not let go), open the vacuum pump to reach a certain vacuum degree before releasing your hand.

5.Method to adjust the host height:Press down the pressure bar at the bottom of the heating tank, adjust the radian left and right to make the host machine reach the proper position, and then the required height can be reached by leaving the pressure bar.

6.Turn on the speed switch green light, adjust the speed knob next to the left side, and the evaporation bottle starts to rotate. Turn on the temperature switch green light, adjust the temperature adjustment knob heating tank on the left side to start automatic temperature control heating, and steam into the trial run. The temperature and vacuum can be evaporated to the receiving bottle as soon as the desired range is reached.

7. Turn off the low temperature coolant circulating pump, turn off the water bath to heat, turn off the pump circulating water, pour out the solvent in the receiving bottle, wash the buffer ball, and receive the bottle. After steaming, stop rotating, then pass the atmosphere, then stop the pump, and finally remove the distillation flask.

8. After the evaporation is completed, first turn off the speed-regulating switch and the temperature-regulating switch, and press the lower pressure rod to raise the main unit. Then close the vacuum pump and open the vent valve above the condenser to communicate with the atmosphere. Remove the evaporator and the evaporation process is over.

Rotary Evaporator Series

  • 10L– 50L Rotary Evaporator (Rotovap)





  • Teflon(PTFE) and fluorine rubber double rotating seal, patent technology to ensure high vacuum
  • The temperature control system, accurate and reliable.
  • In does not affect the system and solution under the condition of vacuum distillation. continuous collection
  • The PTFE disscharge valve, corrosion resistance, no pollution.
  • We have two kinds of conventional and explosion-proof type, can be selected according to the experimental environment.

Technical Specifications

Model R-1005 R-1010 R-1020 R-1050
Evaporating flask 5L, flange opening: Φ50mm 10L, flange opening: Φ95mm 20L, flange opening: Φ125mm 50L, flange opening: Φ125mm
Receiving flask(L) 3 5 10 20
Speed-regulation DC stepless speed-regulation
Power supply 220V-240V, 50/60Hz 3~, 380V, 50Hz
Overall power(kW) 2.3 3.8 6.3 6.3
Rotation speed (rpm) 20~140 20~130 20~130 20~110
Power of motor(w) 250 250 250 250
Condenser Vertical type double coil pipe Vertical type, Main + auxiliary triple-circulating cold traps
Bath material Stainless steel 304
Temperature range RT~99℃
Temperature display Digital display
Sealing 20mbar/h
Evaporating Speed (L/h)(water) 2.0 3.2 5.0 9.0
Evaporating Speed (L/h)(Ethanol) 5.4 8.6 14.3 24.5
Lifting function Motorized Lift Motorized lift + Manual lift
Elevating stroke(mm) 0~150 0~160 0~190 0~180
Dimensions(mm) 835W×400D×1090H 990W×550D×1655H 1195W×635D×2070H 1345W×770D×2140H
Net Weight(kg) 60 85 115 200

10L/20L/50L Pilot system


  • 2L– 5L LAB Rotary Evaporator (Rotovap)






  • Rotary vacuum evaporator Under the vacuum condition, give the boil flask constant-temperature heating, it will  rotate at a constant speed, and liquid can form large area film on the bottle wall.
  • Rotary evaporator parts-the solvent vapor is cooled by a high efficiency glass condenser and recovered in the collection bottle, which greatly improves the evaporation efficiency.
  • Rotary evaporator is especially suitable for the concentration and purification of biological products which can easily decompose and denatured at high temperature.
  • Evaporator use polythene & rubber for sealing, ensure high vacuum and rotating speed adjustable(step-less): 0-90rpm.

Technical Specifications

Model RE-201D RE-301 RE-501
Glass Material GG-17 GG-17 GG-17
Support Material Stainless Steel Stainless Steel stainless steel
Shell Material Antisepsis Plastic Spraying 270*270*195mm Antisepsis Plastic Spraying 290*296*240mm Antisepsis Plastic Spraying 310*320*240mm
Inner Container Material Stainless Steel 250*140mm Stainless Steel 255*170mm stainless steel 280*170mm
Baseboard Size 280*330mm 350*330mm 350*330mm
Volume of Rotary Bottle 0.25-2L 24#Standard Aperture 3L ¢50 flange aperture 5L ¢50 flange aperture
Volume of Recycling Bottle 1L 24#Standard Aperture 2L 35# ground aperture 3L 35# ground aperture
Vacuum Degree 0.098Mpa 0.098Mpa 0.098Mpa
Rotating Power 40W 40W 40W
Rotating Speed 0-120rpm 0-120rpm 0-120rpm
Heating Power 1.5KW 2KW 2KW
Temperature Control Range of Bath Kettle 300℃ 400℃ 400℃
Temperature Accuracy ±2℃ ±1℃ ±1℃
Voltage/Frequency (V/Hz) 220V/50Hz 220V/50Hz 220V/50Hz
Up and Down Distance 120mm 120mm 120mm
Shape Size(mm*mm*mm) 700*440*885 700*440*885 700*335*1009mm
Package Size(mm*mm*mm) 590*460*460 0.12 m³ 1000*460*460 0.12 m³ 1040*620*410 0.26 m³
Package Weight (KG) 21 38 38
Speed Adjustment Mode Electrodeless Speed Regulation Electrodeless Speed Regulation Electrodeless Speed Regulation
Rotate Speed Display Mode Digital Display Digital Display Digital Display

2L/3L/5L Pilot system

Cannabis extraction equipment:Theory of rotary evaporator

  • Vacuum Pump



Technical Specifications

Power (W) 180
Power Supply 110v (1 Phase, 60Hz) or 220-240V (1 phase, 50/60Hz)
Flow Rate (L/min) 80
Lift (m) 10
Ultimate Vacuum (MPa) -0.098 (2KPa)
Single Tap Air Suction Amount 10
Tap Number 2
Safety Check Valve
Water Tank Capacity (L) 15
Water Tank Material PP
Dimensions (mm) 385W*280D*420H
Weight (kg) 11

  • Cooling Circulator




Technical Specifications

Model DLSB-10/30
Temperature range(°C) -30~Room temp
Temperature stability(°C) ±2
Cooling capacity (W) 10°C 1860
0°C 1240
-10°C 780
-20°C 310
-30°C 50
Flow(L/min) 12
Lift(m) 5~7
Bath volume(L) 10
Bath opening(mm) Diameter 210×250
Ambient temperature(°C) 5~25
Power Supply(V/Hz) 220/50
Overall Power(W) 1100
MaterialsOf Machine Casing SPCC steel with powder coating
Dimensions(mm) 510L×365W×800H
Weight(kg) 50

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