Before choosing a rotary evaporation instrument, ask yourself the following questions: What is the amount of distillation? What is the number of samples that need to be distilled every day? What are the distilled solvents? What is the range of the boiling point of the solvent? Are these solvents be flammable and explosive, or toxic and harmful solvents? Once the experimental requirements and distillation solvent types are determined, we can start to choose a rotary evaporation instrument!
The specifications of the specifications of the evaporative evaporation instrument are usually distinguished in the volume of the evaporation bottle. The size of the evaporative bottle depends on the number of evaporation materials. Generally speaking, 2L, 3L, 5L rotating evaporator is suitable for small laboratory small Quantitative test; 5L, 10L, 20L are suitable for middle test; 20L, 50L are suitable for middle test and production. Of course, in special circumstances, we can also use the continuous feeding tube to expand the volume of evaporate bottle, thereby expanding the continuous distillation to a certain extent.
. Clarifying the required distillation task distillation efficiency of the rotary evaporate instrument is very critical. The distillation efficiency of the spinning evaporator determines the number of samples that can be distilled every day. In the case of the same solvents, the higher the distillation efficiency, and the number of distillation samples is also. more. If the sample volume is large, we are thinking about distillation efficiency.
Key factors affecting distillation efficiency
NO. 1 【The vacuum value of the system】
The closed space of the rotating evaporator consists of glass components such as evaporative bottle, evaporation tube, sealing ring, condensation tube and other glass components, vacuum buffer bottles, vacuum pumps and vacuum pipelines. Among them, the most critical and changeable factors that affect the system vacuum Sealing ring and vacuum tube.
Vacuum pump and vacuum controller: the lower the limit of the vacuum pump, the lower the vacuum value of the system. When distillation, a reasonable vacuum value is required through the vacuum controller to ensure distillation efficiency and avoid explosion.
At present, the limits of the diaphragm vacuum pump can reach the minimum of 2MBAR, and the limit vacuum of the circulating water pump is about 50MBAR (0.095kPa). If the budget allows, the vacuum controller or vacuum valve is necessary, and it can control the vacuum value required for the distillation.
As a key sealing part of the evaporation tube and condensation tube, its abrasion resistance and corrosion resistance are the key.
The material commonly used as a sealing ring is: PTFE and rubber. Obviously, the wear resistance and corrosion resistance of PTFE will be better. In the sealing circle, individual manufacturers have added stainless steel buffer shelters to wear better abrasion resistance.
Vacuum pipe material: Generally, various manufacturers do not standard for vacuum pipes. When purchasing by themselves, the silicone tube is naturally the first choice, because its aging efficiency is slower than that of rubber pipes.
NO.2 【Heating pot temperature】
The higher the temperature of the heating pot, the faster the distillation of the solvent, but considering the thermal sensitivity and operation of the target component, the most commonly used temperature is 60 ° C. Furthermore above 80 ° C, the use of silicon oil as a medium will bring cleaning problems. Generally, it is recommended to reduce the vacuum value to achieve faster distillation efficiency. At present, the best vacuum pump in the market can reach 2MBAR, and DMF can be disturbed at room temperature.
NO.3 【Speed speed of evaporative bottle】
The faster the speed of the evaporative bottle, the larger the infiltration area of the bottle, the larger the heating area; but at the same time, the thicker the thickness of the liquid film, the increase in heat transfer temperature. For different viscosity materials, there is the best speed. And the rotation power is provided by the motor. DC brush -free motor, AC motor and step motor are all available on the market. There are unevenness. The feedback of DC without brush motor is the best.
NO.4 【The temperature of the cooling medium】
In order to ensure the best distillation efficiency, cooling medium is generally recommended to maintain a temperature difference of 40 ° C with the temperature of the heating cooker, so as to quickly condense thermal steam and reduce the impact of steam on the system vacuum. Safety risk assessment of distillation safety risks mainly derived from distillation solvents and heating media.
1) If the heating medium is silicon oil, the ignition point is at least higher than the maximum temperature of the heating cooker by 25 ° C.
2) If the distillation solvents are flammable and explosive, explosion -proof glass components can be used as the first choice, and the distillation is over. If the instrument can automatically relieve the best, it is best to avoid artificially air -to -way and cause explosion.
3) Optimize the laboratory environment, you can select the secondary condensate device to maximize the recycling of distillation solvents.
4) After -sales service after -sales service does not need to be more analyzed. The after -sales sales of imported brands is better than domestic brands. The import brand services in domestic factories are the best, and the response is the fastest. It is not worried that “manufacturers escape”.
Fan Q & A
1. Q: What is the working principle of a rotary evaporator?
Answer: Under the negative pressure conditions, the evaporative bottle rotates in the constant temperature water bath, and the solution forms a thin film on the wall of the bottle to increase the evaporation area. Efficient evaporation at low temperature, condensation recycling, concentrated separation materials.
2. Q: What is the core technology of rotating evaporator?
Answer: It is the system of the system, that is, under the erosion of various solvents, whether the system can maintain high vacuum in the state of movement. The R-series rotating evaporator is sealing with Teflon materials and glass. It can withstand various solvents. It has a long-lasting and reliable gas tightness and can maintain a high-authenticity above -0.098MPa.
3. Q: What are the main factors that affect the efficiency of rotating evaporators?
Answer: As far as the same specifications are concerned, it is mainly: steam temperature, real vacuum and cooling water temperature. It is restricted by the heat resistance of certain materials, and it is impossible to increase the steam temperature infinitely during work. It can be equipped with a variety of types of low temperature pumps).
4. Q: What is the difference between the vertical condenser and the oblique condenser?
Answer: There is no obvious difference in nature. The vertical condenser is gradually welcomed due to small occupation space. Large -capacity evaporator generally uses a vertical condenser.
5. Q: What is the basis for the design of the host lift and the water bath?
Answer: Based on the principle of convenience, safety and economy, general small machines (less than 5L) lifting hosts internationally internationally, the humidity sensor probe, stainless steel electric heating pipe, PT100 sensor, fluid solenoid valve, aluminum heating device, heating circle, heating circle, heating circle Essence
6. Q: What is the explosion resistance of the R series evaporator?
Answer: The rotary evaporator produced by our company uses an AC motor, has a stepless speed regulation (or variable frequency speed regulation), no brush, no spark during operation. The control of the water bath and cooker in conjunction uses nitrogen -filled seal relay, respectively, with no contact switch and vacuum switch. The manual control switch is controlled by the secondary line, the control current is less than 3mA, and it has good explosion -proof characteristics. At the same time, we are equipped with explosion -proof motors, explosion -proof electronics, explosion -proof lines, explosion -proof electric heater, and safe and reliable, so that you do not care about it during experiments.
7. Q: How to buy various types of rotary evaporator?
Answer: In terms of structure, the R -series rotating and evaporators produced by our factory have good corrosion resistance and sealing. 2L, 3L, 5L machines are suitable for laboratories and sample tests; 5L, 10L, 20L are suitable for middle tests; 20L and 50L are suitable for middle test and production, especially for avoiding the extraction of metal ion pollution materials.
8. Q: How does the rotary evaporator compare with other types of evaporator?
Answer: Its main advantage is that the structure is small, compact and efficient, intuitive work, and no metal ion pollution. Applicable to laboratory, production test, and extraction of valuable materials. Its sealing performance is comparable to foreign machinery.
9. Q: How to choose a vacuum pump for rotating evaporator?
Answer: We recommend circulating water vacuum pumps. Its advantage is that various solvents are resistant to corrosion, which can be vacuum to -0.098MPa (to meet the requirements of use). Vacuum pumps can be used according to the size of the evaporator volume, and different models are selected. Our factory can support various types of vacuum pumps.