The origin of vacuum drying oven is relatively early. The principle is that the drying box is layered by a heating plate, hot water or low-pressure steam is introduced into the heating plate as a medium, then the tray containing the medicine to be dried is placed on the drying plate, the door of the box is closed, and the air in the box is pumped out by a vacuum pump to form a vacuum environment. The heating plate heats the medicine to the specified temperature in the circulating flow of the heating medium, and the water begins to evaporate and is gradually pumped away with the action of the vacuum pump. This kind of drying equipment is easy to control, and the medicine is not easy to be polluted during the drying process, so it is suitable for medicine drying and packaging sterilization.
Vacuum rotary dryer comes from double-cone mixer, mostly cylindrical, with conical ends, also known as double-cone dryer. There are two hollow suspension shafts in the middle of the cone, which are used for rotating support of equipment and the passage of vacuum and hot water. The medicine rotates while drying in the dryer, which ensures the uniform import of the whole batch of medicine. The heat medium enters the jacket from the hollow tube at one end, the hot gas in the container is discharged from the exhaust pipe in the hollow tube at the other end, and the volatile solvent is recovered by condensation. Because of its simple operation and easy adjustment of intermittent production, this equipment can be used for online cleaning and online sterilization, making it the first choice for small and medium-sized antibiotic bulk drug enterprises, such as penicillin, lincomycin, chlortetracycline and caffeine.
Three-in-one equipment, the so-called three-in-one equipment refers to the three processes of filtration, washing and drying. The three important processes are perfectly combined by the three-in-one equipment, mainly because the filter belt is pushed in different ways and the workflow is exactly the same. The material is evenly spread on the filter belt by the feeder, and the filter belt is dragged by the transmission device to move in the dryer. Washing and filtering the solvent in the section, and recovering the solvent mother liquor by vacuum cold pumping; Hot air enters the drying section, and the solvent is removed in vacuum, condensed and recovered. Used in mass production, suitable for drying granular materials with good air permeability, and the finished products are dried evenly, which is widely used in vitamin C and penicillin industries in China. Because the equipment is relatively closed, online cleaning and online sterilization can not be arranged well, so it is only suitable for drying non-sterile raw materials and pharmaceutical intermediates.
Freeze-dryer is suitable for drying heat-sensitive or easily oxidized drugs, commonly known as freeze-dryer, which mainly includes freeze-drying box, vacuum system, heating system and refrigeration system. Freeze dryers are widely used to dry raw materials and pharmaceutical preparations. The main requirements are high reliability, complete sterilization function, and the temperature difference between the same shelf and between plates is not more than 65438 0.5℃ [2], which also requires better flatness of the shelf. When using this equipment to dry raw materials, it is best to add a powder mixer to ensure the uniformity of products. Most ampicillin, a large number of blood products, artificially cultured drugs, antibodies, vaccines, etc. It's freeze-dried.
The pneumatic drying device is suitable for granular and powdery materials which are easy to dehydrate, and can quickly remove water (mainly surface water) from the materials. In airflow drying, the quality of dried products is best controlled because the material stays in the dryer for a short time. The wet material is fully mixed with the hot air flow through the feeder, and enters the drying pipe under the attraction of the wind for further uniform drying. Wet and heavy particles that cannot be attracted by the wind continue to be hit, broken and dried in the dryer until they can be sucked up by the wind and enter the drying pipe, and the end of the drying pipe is a cyclone separator. This equipment is mainly used for the production of oxytetracycline and some health products in pharmaceutical industry.
The working principle of spray dryer is similar to airflow drying. The air is heated by the heater after preliminary filtration, and the generated hot air is filtered in multiple stages (selected according to the drug grade), and then the hot air distributor in the volute channel at the top of the drying chamber generates uniform rotating airflow and enters the drying chamber. The material is filtered by centrifugal atomizing disc or pressure nozzle, resulting in finely dispersed material fog. The material mist comes into contact with the rotating hot air, and the water evaporates quickly, which makes the material dry in a short time. This equipment is suitable for drying liquid materials with good fluidity, such as solution, emulsion, suspension and paste. Now, the equipment can be used for drying raw material medicine industries such as streptomycin, gentamicin and various biological extracts.