Rotary evaporators are mainly used for concentration, crystallization, drying, separation and solvent recovery in the pharmaceutical, chemical and biopharmaceutical industries.
The current prices of rotary evaporators on the market vary according to different models and brands.
In recent years, with the continuous development of my country's pharmaceutical and biopharmaceutical industries, some domestic rotary evaporator manufacturers have developed new rotary evaporators based on the needs of current domestic and foreign laboratory users. The instruments are equipped with more new safety functions and digital connection functions, etc., the product stability is improved, and the price is more favorable than imported products.
So, in addition to considering price factors, how should buyers choose rotary evaporators? Some manufacturers' technicians suggest that when purchasing a rotary evaporator, the specifications of the rotary evaporator should be selected first.
It is reported that the specifications of the rotary evaporator are distinguished by the volume of the evaporating flask, and the size of the required evaporating flask depends on the amount of evaporated material.
Generally speaking, 2L, 3L, and 5L rotary evaporators are suitable for small-scale laboratory tests; 5L, 10L, and 20L are suitable for pilot tests; 20L and 50L are suitable for pilot tests and production.
Secondly, consider the evaporation rate of the rotary evaporator. It is understood that for the same specification of rotary evaporator, there are four main factors that affect the evaporation rate of the rotary evaporator: heating bath temperature, vacuum degree in the rotary evaporator, condenser cooling medium temperature and evaporation bottle speed.
Specifically, in terms of heating bath temperature, the higher the heating bath temperature, the more intense the evaporation of the material. However, due to the constraints of material thermal tolerance, safety of use and energy consumption, the commonly used temperature is 60°C. The industry said that the heating bath temperature is moderate, the volatilization rate of water is low, and the energy utilization rate is high.
In terms of the vacuum degree in the rotary evaporator, the industry recommends a vacuum degree of 95-98kPa (absolute pressure 2-5kPa); in terms of the condenser cooling medium temperature, the relationship between the material temperature and the vacuum degree conforms to the relationship between the material saturation temperature and the saturation pressure. When the heating bath temperature and vacuum degree are determined, the cooling medium temperature depends on the type of material.
In addition, in terms of the evaporation bottle speed, the higher the evaporation bottle speed, the larger the infiltration area of the inner surface of the bottle, and the larger the heating area; but at the same time, the thickness of the liquid film is also thicker, increasing the heat transfer temperature difference. For materials with different viscosities, there is a rotation speed.
After considering the evaporation rate of the rotary evaporator, select the supporting equipment. The supporting equipment of the rotary evaporator refers to the vacuum equipment and the cold source equipment.
The industry recommends that the vacuum pump should use a circulating water vacuum pump or a diaphragm vacuum pump that is resistant to corrosion by various solvents. A vacuum controller can be optionally equipped to achieve a more efficient and controllable distillation process. In addition, the cold source equipment is selected according to the cooling medium temperature and evaporation amount.