Structural Principle, Components, And Instructions Of Rotary Evaporator

Hawach rotary evaporator uses a motor to drive the distillation bottle to rotate. Because the distiller is constantly rotating, zeolite can be added without bumping. At the same time, due to continuous rotation, the liquid is attached to the wall of the distiller, forming a liquid film, which increases the evaporation area and accelerates the evaporation rate.

Pay attention to: (1) During vacuum distillation, when the temperature is high and the vacuum is low, the liquid in the bottle may bump. At this time, the vacuum should be reduced in order to carry out the distillation smoothly. (2) When the evaporation is stopped, first stop the heating, then stop the vacuum, and finally cut off the power to stop the rotation.

Structural principle
Structure: The distillation 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, and the other opening of the reflux condenser tube is connected to a receiving flask with a grinding port. For receiving evaporated organic solvents. When the system is open to the atmosphere, the distillation flask and the liquid-contacting flask can be removed to transfer the solvent.

When the system is connected to the pressure-reducing pump, the system should be Pressure state. When in use, the pressure should be reduced first, and then the motor should be turned to rotate the distillation flask. In the end, it should be shut down before venting to the atmosphere to prevent the distillation flask from falling off during rotation. As a heat source for distillation, it is often equipped with a corresponding constant temperature water tank.

Working principle
The vacuum flask was placed under negative pressure by a vacuum pump. The evaporation flask is placed in a water bath and heated at a constant temperature while rotating. The solution in the bottle is heated and diffused and evaporated in the rotating flask under negative pressure.

The rotary evaporator system can seal and reduce the pressure to 400-600 mm Hg; use a heating bath to heat the solvent in the distillation flask, the heating temperature can be close to the boiling point of the solvent; at the same time, it can also be rotated at a speed of 50-160 rpm, Make the solvent form a thin film and increase the evaporation area. In addition, under the action of a high-efficiency cooler, the hot steam can be quickly liquefied to speed up the evaporation rate.

The main components
1. Rotating motor, which drives the evaporation flask containing the sample through the rotation of the motor;
2. Evaporation tube. The evaporation tube has two functions. First, it functions as the sample rotating support shaft, and secondly, through the evaporation tube, the vacuum system sucks the sample;
3. Vacuum system to reduce the air pressure of the rotary evaporator system;
4. Fluid heating pot, usually the sample is heated with water;
5. Condensation tube, use double serpentine condensation or other condensing agents such as dry ice and acetone to condense the sample;
6. Condensate the sample collection bottle. After the sample cools, enter the collection bottle.

Mechanical or motor mechanical devices are used to quickly raise the evaporating bottle in the heating pot.

The vacuum system of the rotary evaporator can make a simple water suction pump immersed in a cold water bath, or a mechanical vacuum pump with a cooling tube. Evaporating and condensing glass components can be simple or complex, depending on the distillation objective and the characteristics of the solvent to be distilled. Different commercial equipment will contain some basic features. Modern equipment usually adds functions such as digitally controlled vacuum pumps, digital display of heating temperature, and even steam temperature.

1. High and low adjustment: manual lifting, turning the handwheel above the machine column, the forward rotation is rising, and the reverse rotation is falling.
Electric lift, the cost rises by touching the up button, the host descends by touching the down button.
2. There are two external connectors on the condenser for cooling water, one end is connected to the water, and the other end is connected to the outlet water. Generally, it is connected to the tap water. The lower the temperature of the condensate, the better the effect. The upper part is equipped with a vacuum connection and a vacuum pump hose Used for vacuuming.
3. Before turning on the power, turn the speed control knob to the minimum, press the power switch to turn on the light, and then slowly turn to the right speed. Generally, for large evaporation bottles, use medium, low speed, and high viscosity solutions. Use lower speed. Flask It is standard interface No. 24, 500ml and 1000ml flasks are attached at random, and the amount of solution is generally not more than 50%.
4. When using, you should first reduce the pressure, and then start the motor to rotate the distillation flask. In the end, the motor is stopped first, and then the atmosphere is vented to prevent the distillation flask from falling off during rotation.

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