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Eight common problems and maintenance of rotary evaporators

Rotary evaporator is an indispensable instrument for evaporation, concentration, crystallization, drying, separation and solvent recovery in scientific research and production processes in the pharmaceutical, chemical and biological products industries. The basic principle of a rotary evaporator is vacuum distillation, which is mainly used to continuously distill a large amount of volatile solvents under reduced pressure. The reaction product can be separated and purified by concentration of the extract and distillation of the receiving liquid during chromatographic separation. In the form of scene-reproduction communication, I compiled the eight common problems and maintenance of rotary evaporators.

Firstly, let’s explore the eight common problems of rotary evaporators.

rotary evaporator

rotary evaporator

  1. Q: What is the working principle of the rotary evaporator?

Answer: Under the negative pressure working condition, the evaporation flask of the rotary evaporator is continuously rotated in the constant temperature water bath, so that the solvent solution forms a film on the bottle wall to increase the evaporation area of the solution. High-efficiency evaporation at low temperature and condensation recovery through the condenser, concentration and separation of materials to meet the experimental requirements.

  1. Q: What is the core technology of the Lanphan Rotary Evaporator compared to similar products?

A: The air tightness and high vacuum of the system during operation are the key to the operation of the rotary evaporator. Henan Lanphan’s R series rotary evaporator is sealed with rubber PTFE composite material and glass. It can withstand various solvents, has a durable and reliable air tightness, and can maintain a high vacuum of -0.096MPa or more.

  1. Q: What is the decision on the working efficiency of the rotary evaporator?

Answer: For rotary evaporators of the same specification type, the steam temperature will be limited due to the heat resistance of some materials. Therefore, high vacuum and low cooling water temperature are the two main factors to improve efficiency ( Cryopumps can be used and water temperature can be lowered).

  1. Q: What is the difference between a vertical and a diagonal condenser?

A: There is no difference in essence between the two. The vertical condenser is gradually welcomed due to its small footprint and convenient transportation. Large-capacity rotary evaporators use more vertical condensers.

rotary evaporator

rotary evaporator

  1. Q: Is there any basis for the design of the main engine lifting and water bath lifting?

Answer: The difference between the lifting methods is mainly from the aspects of convenience, safety and economy. Generally, the small rotary evaporator below 5L adopts the lifting main mode, while the rotary evaporator above 5L adopts the lifting water bath.

  1. Q: What is the explosion-proof characteristic of the R series rotary evaporator?

A: Our company’s rotary evaporator uses AC motor, stepless speed regulation (or variable frequency speed regulation), no brush, no spark during operation. The matching water bath is controlled by a nitrogen-filled sealed relay, and the thyristor non-contact switch vacuum switch. The manual control switch adopts secondary line control, and the control current is less than 3mA with good explosion-proof characteristics.

  1. Q: What is the basis for the rotary evaporator model selection?

Answer: According to the amount of solvent in the experiment, 2L, 3L, 5L capacity rotary evaporator is suitable for laboratory and sample test. The 5L, 10L, and 20L capacities are suitable for the pilot test. The 20L and 50L capacities are suitable for pilot and production, especially for the extraction of metal ion contaminants.

  1. Q: How do I use a vacuum pump for a rotary evaporator?

A: The rotary pump of the rotary evaporator we recommend the water circulation pump, which can withstand various solvent corrosion and vacuum to -0.095MPa. According to the volume of the rotary evaporator, our factory can supply various types of vacuum pumps.

Secondly, I want to tell you about the maintenance of the rotary evaporator.

rotary evaporator

rotary evaporator

  1. Rotary evaporation instrument maintenance

(1) Carefully check the glass bottle for damage and interface.

(2) Wipe each interface with a soft cloth and apply a proper amount of vacuum grease to prevent dust from entering.

(3) Regularly loosening the interfaces to avoid long-term tight locking and the connector cannot rotate.

(4) Turn on the power switch first and gradually increase the speed of the machine. When turning off the switch, first make sure the experimental instrument is stopped.

(5) The PTFE switch in all places cannot be tightened too much and it is easy to damage the glass.

(6) Avoid long-term static work in the working state to deform the PTFE piston, and tighten the PTFE switches after shutdown.

(7) Clean the seals regularly.

(8) The electrical part should pay attention to moisture.

  1. Rotary head seal maintenance

The end face is sealed between the rotating bottle and the rotating head. If the O-ring is damaged, it should be replaced in time. Attached to the standard, it is a standard part, and users can purchase it by themselves. The air guide shaft is not rotated, and the spindle seal of the rotary head is borne by the skeleton oil seal. Due to the use of PTFE gland insulation in the design, the vapor of the organic solvent is difficult to corrode, and the normal service life can reach more than half a year. During maintenance, the Teflon sealing sleeve can be pulled out to observe whether the oil seal is intact. If it is found to be worn, aged or the solution is invalid, it should be replaced in time. When replacing, please purchase the same size imported oil seal.

  1. Rotary head lubrication maintenance

The normal rotating head should be flexible by hand, without jamming, pinching, and light weight. Lubrication failure will use motor heating, PTFE sleeves and oil seals are damaged, so regular maintenance is necessary.

(1) Once a month, put the Teflon sleeve down and clean the outer circumference of the air guide shaft and the Teflon sleeve and the inner hole of the oil seal. Reapply a high-grade grease with a temperature resistance of 120 ° C or higher. After recovery, wipe off the extruded grease.

(2) Once a month, remove the gas cylinder, pull out the air guide shaft from the left end of the machine head, clean the machine head, and reapply high-grade grease on each lubrication surface. Remove the 2 5M screws under the machine head, remove the motor, clean the shift gear, and re-grease the grease. (Operation is normal, the maintenance period can be extended, if the organic solution flows into the machine head, the lubrication part should be cleaned in time.)

  1. Instrument and equipment cleaning method

Care should be taken when cleaning the glass. If the standard port is caught for a long time, it can be heated and then rotated out. If you have any questions during use, you can contact Lanphan.

(1) For general equipment, you can brush off the impurities with water or soap from the outside to the inside and then rinse the inner wall with distilled or deionized water two or three times. For glass equipment with grinding, you should pay attention to protect the grinding when washing.

(2) Glass equipment that is not easy to be brushed with a brush or brushed with a brush is usually poured into a container or immersed in a container, and then poured out with tap water and deionized water.

(3) The sand core glass filter should be cleaned immediately after use. Dissolve the surface precipitate with a suitable detergent according to the sediment in the sand core, rinse it with distilled water, dry it at 110 °C, and store it in a dustproof cabinet.

rotary evaporator

rotary evaporator

The above mentioned text is the introduction of the eight common problems and maintenance of rotary evaporators. If you want to know more about rotary evaporator, please contact with the henan lanphan. Henan lanphan is a qualified company, which boasts good reputation both home and abroad. For several years, we are dedicated to the manufacture of laboratory equipment and pipe fittings. If you want to know more more about this or possess the intention to buy it, please contact with us as soon as possible.

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