Are You Using the Industrial Rotary Evaporator Correctly?

For the industrial rotary evaporator, good equipment is half of the success. At the same time, how to operate the laboratory rotary evaporator correctly, increase the service life of the equipment, and reduce maintenance costs is also a topic of great concern to all scientific researchers.

In the process of using the laboratory rotary evaporator water bath, the above two situations are often encountered. No matter which one, it looks unsightly, so how to solve it? First of all, the inner tank of most of the water baths on the market is made of stainless steel. On the one hand, it comes from the good thermal conductivity of stainless steel, and it is durable and beautiful. At the same time, compared with other materials of the water bath, the stainless steel inner tank is more convenient in removing impurities such as scale. The main reason for the above two situations is that you heat the “water” used in the pot.

During the experiment, many experimenters cherish the industrial rotary evaporator much, and also hope to give thousands of favors to the water bath, and choose the best raw materials. Therefore, for the water in the heating pot, some experimenters will use “deionized water”. As everyone knows, high-purity deionized water is precisely the culprit for the rust of the water bath.

Since the number of ions in deionized water can be controlled artificially, its resistivity, solubility, and corrosion physical, chemical and pathological indicators such as virus and bacteria are well controlled, and industrial rotary evaporator deionized water is also widely used in laboratories. But is it feasible to use deionized water as a heating bath?


Generally speaking, this kind of deionized water will have certain acid-base problems. When the deionized water encounters stainless steel, a certain electrochemical reaction will naturally occur, which is simply the transfer of charge.

The result of this transfer will cause the electrons of the metal elements in the stainless steel to be absorbed, and some of the exposed anode electrons, such as industrial rotary evaporator positive iron ions, encounter oxygen in the air because the electrode potential of iron is always higher than that of oxygen. Low, so iron will be corroded as a negative electrode.

We will see that many small bulges of varying diameters are formed on the surface where oxygen corrosion occurs, and the second layer is black powdery ulcers and corroded pits, resulting in damage to the stainless steel container. At the same time, this laboratory rotary evaporator reaction is irreversible, which is one of the important reasons why high-purity deionized water cannot be stored or transported in stainless steel containers.

Similarly, the distilled water or desalinated water in the laboratory is not suitable for stainless steel heating pots. Distilled water generally refers to water from which anions and cations dissolved in it have been removed. Therefore, laboratory rotary evaporator water has a tendency to restore these cations and anions in order to saturate them again. So it becomes “hungry”.

In order to satisfy hunger, water will dissolve ions in metals and carbon dioxide in the air to turn into carbonic acid. This leads to the pH of the distilled water at around 5, that is, in the acidic range, the metal will corrode. So, really take good care of your heating pot, please try not to use the above water quality for heating operation.

In addition to deionized water or high-purity water, the most commonly used in the laboratory is ordinary tap water solution. Tap water has a low cost and is not easy to rust. However, for heating pots operated with tap water, the accumulation of scale will inevitably occur for a period of time. Limescale is actually the accumulation of calcium and magnesium in tap water.

Due to certain differences in water hardness across the country, the conditions of the heating pot after using tap water are also slightly different. Although the scale has little effect on the heating pot itself, it has a great impact on the appearance, and it will also affect the heat transfer efficiency for a long time. Therefore, regular cleaning of scale is also a necessary course for laboratory water bath maintenance.

To remove scale, commonly used ones include baking soda, acetic acid, citric acid, etc. In the laboratory, we recommend that you use low-concentration citric acid to clean the water bath regularly. On the one hand, citric acid can effectively dissolve the scale and make your water bath clean as new. On the other hand, citric acid is a weakly acidic organic acid and does not contain chloride ions. It has minimal damage to metal components and can better protect the heating pot from damage. In addition, when you use tap water for heating, adding a certain proportion of pure water can also delay the formation of scale.

The operation of the industrial rotary evaporator rotating motor requires an electric drive, and the operation of the motor on the rotary evaporator requires a uniform speed operation so that the distillation flask is driven to rotate at a uniform speed. It should be said that such a rotation method is more in line with various experiments. Here we mainly understand the two important functions of the laboratory rotary evaporator evaporating glass tube.

On the one hand, the evaporating glass tube can serve the purpose of supporting and protecting when the sample is rotated. Another function is that the political and legal glass tube can realize the vacuum device to extract the samples.

It is necessary to know that the vacuum device on the industrial rotary evaporator can greatly reduce the overall air pressure on the rotary evaporator, which is conducive to the normal conduct of the experiment. The main function of the accessories on such a distillation apparatus is to heat the sample, and then better control the required temperature to reach the required temperature. The main purpose of use: to condense the sample.