Rotary evaporator principle and common problem solution

Rotary evaporator structure principle

Structure: The distillation flask can be an eggplant-shaped or round bottom flask with a standard ground port, connected to a pressure reducing pump via a highly refluxing serpentine condenser, and the other opening of the reflux condenser is connected to a receiving flask with a grinding port. It is used to receive the evaporated organic solvent. There is a three-way piston between the condensing pipe and the decompression pump. When the system is connected to the atmosphere, the distillation flask and the liquid-receiving flask can be removed and the solvent is transferred. When the system is connected with the decompression pump, the system should be reduced. Pressure state. When using, depressurize first, then start the motor to rotate the distillation flask. At the end, stop the machine and then pass 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.

Rotary evaporator working principle

RE-5003 Rotary Evaporator

By 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 by a vacuum pump. 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 rotary evaporator system can seal the pressure to 400~600 mmHg; the solvent in the distillation flask is heated by a heating bath, the heating temperature can be close to the boiling point of the solvent; and the rotation can be performed at a speed of 50-160 rpm. The solvent is formed into a film to increase the evaporation area. In addition, under the action of a high-efficiency cooler, the hot vapor can be quickly liquefied to accelerate the evaporation rate.

The main components

1. Rotating the motor to drive the evaporation bottle containing the sample by the rotation of the motor;

2, the evaporation tube, the evaporation tube has two functions, first to play the role of the sample rotation support shaft, and secondly through the evaporation tube, the vacuum system to suck the sample;

3. A vacuum system for reducing the pressure of the rotary evaporator system;

4, the fluid heating pot, usually under water to heat the sample;

5, the condensation tube, using double serpentine condensation or other condensing agents such as dry ice, acetone condensation samples;

6. Condensate the sample collection bottle. After the sample is cooled, it enters the collection bottle.

Mechanical or motor mechanisms are used to quickly lift the evaporation flask in the heating pot.

The rotary evaporator's vacuum system allows for a simple water immersion pump that is 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 purpose of the distillation and the nature of the solvent to be distilled. Different commercial devices contain some basic features, and modern devices often add features such as digitally controlled vacuum pumps, digital display heating temperatures, and even steam temperatures.

Rotary evaporator use method

1. Height adjustment: manually lift, turn the hand wheel above the machine column, turn to rise, reverse to decrease.

Electric lift, the hand touches the rise button and the main unit rises, and the hand touches the down button to lower the main unit.

2. There are two external joints on the condenser for connecting the cooling water. One end is connected to the water and the other end is connected to the water. Generally, the tap water is connected. The lower the temperature of the condensed water, the better the effect. The upper port is equipped with a vacuum connector and the vacuum pump tube is connected. Vacuuming.

3. Turn the speed control knob to the minimum before starting the machine, press the power switch indicator light, then slowly turn right to the required speed. Generally, the large evaporation bottle is used in medium, low speed, high viscosity solution with lower speed. Is the standard interface No. 24, with 500ml, 1000ml two flasks, the amount of solution is generally not more than 50% is appropriate.

4. When using, depressurize first, then start the motor to rotate the distillation flask. At the end, stop the motor and then pass the atmosphere to prevent the distillation flask from falling off during the rotation.

Common problems and solutions

The motor does not turn

1. The indicator light (or digital display) of the electric control box is on, and it is detected whether the external plug connection inside the electric box is loose or broken. (Test content)

2. The indicator light (or digital display) of the electric control box does not light up. (Test content)

3. Confirm that there is no abnormality in "1, 2". (Test content)

4. The inverter is displayed by the high frequency interference "OU". (Test content)

5. The inverter protection function can be displayed. (Test content)

1. Re-plug and disconnect the wire. (solution)

2. Update the fuse or confirm that there is no abnormality in the power supply. (solution)

3. Update the circuit board or electric control box. (solution)

4. Complete the ground line or change the work location. (solution)

5. Exclude according to the inverter manual P33. (solution)

The bath is not heated

1, the bath is countless. (Test content)

2. The "OUT" or "ON" green indicator in the temperature controller is not lit. (Test content)

3. When the bath temperature is lower than the set temperature, the "OUT" or "ON" green indicator in the temperature controller does not light. (Test content)

4. “OVER” or “000” is displayed on the temperature controller. (Test content)

1. Detect the power supply 220V. (solution)

2. Change the heating coil. Replace the solid state relay or relay board. (solution)

3. Change the temperature controller. (solution)

4. Detect probe wiring or update the probe. (solution)

Bath pot temperature

1. When the bath temperature is higher than the set temperature, the "OUT" or "ON" green indicator in the temperature controller will not be extinguished. (1-2°C is normal) (test content)

2. The "OUT" or "ON" green indicator in the temperature controller has been extinguished and heating continues. (Test content)

3, the digital bath temperature is far lower than the actual bath temperature. (Test content)

1. Change the temperature controller. (solution)

2. Change the solid state relay or relay board. (solution)

3. Change the probe or temperature controller. (solution)

Vacuum can't pump

1. There is solvent in the container, which is limited by the pressure of the saturated injector. (Test content)

2. The capacity of the vacuum oil pump is reduced. (Test content)

3, vacuum tube, loose joints, vacuum gauge leak. (Test content)

4. The magnetic particle flaw detector is used for holding pressure test. In the absence of any solvent, all external butterfly valves and pipelines are shut off, and the pressure gauge is kept for one minute. The vacuum gauge pointer should not move, indicating that the airtightness is good, and vice versa. (Test content)

5. There are debris in the discharge valve and pressure control valve. (Test content)

6. The glass wool cotton sandwich panel is damaged. (Test content)

1. Empty the solvent and test the empty bottle. (solution)

2, vacuum oil pump oil (water), cleaning and maintenance. (solution)

3. Detect and eliminate piece by piece along the vacuum pipeline. (solution)

4, 1 re-assembly, glass wool cotton sandwich plate grinding, clean, apply vacuum silicone grease, the flange mouth is aligned and tightened. (solution)

2 Update the failed seal. (solution)

5. Cleaning. (solution)

6, update or repair. (solution)

Motor speed (only the highest speed)

1. Detect whether the speed measuring generator coil is open circuit. Use a multimeter to measure the seven-pin plug "1, 2" feet (both sides of the positive groove) and the normal resistance is about 400Ω. (Test content)

2. The generator coil is shorted to the outer casing. (Test content)

3. The generator magnetic ring does not turn. (Test content)

4. The generator magnetic ring is broken. (Test content)

1. The generator is disconnected, the coil is updated or the breaking point is turned on. (solution)

2. Loosen the motor back cover of the motor to eliminate the short circuit. (solution)

3. Tighten the M5 nut. (solution)

4. Update the generator magnetic ring. (solution)

Motor heating

1. Motor temperature rise (case temperature - room temperature), △T≤40°C is normal (test content)

2. △T>40°C is treated according to the right method. (Test content)

3. The flat display part is shiny, indicating that the motor current is overloaded, and it is processed according to the right method 2. (Test content)

1, do not have to deal with, can continue to use. (solution)

2, 1 reduce the stirring blade to reduce the load. (solution)

2 Avoid the rotational resonance point. (solution)

3 Increase the speed appropriately and use medium speed. (solution)

4 Discharge the mechanical part of the abnormal resistance. (solution)

5 Maintenance of the sealed lubrication part. (solution)