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    Home > Active Ingredient News > Drugs Articles > What are the spray methods for fluidized bed coating machines?

    What are the spray methods for fluidized bed coating machines?

    • Last Update: 2019-01-09
    • Source: Internet
    • Author: User
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    In fluidized bed granulation or pellets and coating process, spray method should be selected according to material properties and product quality in the plan At present, there are three kinds of fluidized bed spray methods, namely, top type spray, tangential spray and bottom type spray (1) most of the top spray products are used in the process of coagulation The particles produced by this method are characterized by porous surface and interstitial cavity The bulk density is small, which is an effective way to increase the dissolution of poorly soluble drugs, because particles or pellets are easy to absorb liquid and disintegrate quickly, such as drying and granulation of Chinese medicine leachate (2) tangential spray, which uses the centrifugal force generated by rotating disc to obtain high intensity mixing effect and combines with the drying efficiency of fluidized bed, produces a product with higher bulk density but still has a small gap and cavity The particle hardness is large, and it is not easy to break and close to globular It is a common method to prepare pellets (3) the bottom type spray is placed in the draft tube at the center of the air distribution plate, and the fluidized pellets, pellets or tablets are used to receive adhesives or coating solutions in the draft tube At present, it is a commonly used way of coating pellets, which has the advantages of high coating efficiency, and the pellets are not easy to adhere Xinyi has developed a modified fluidized bed which can adjust the internal and external air volume of the draft tube online, and the spray device can be cleaned online, greatly improving the controllability of pellets coated in fluidized beds The above three spray methods can be used to prepare pellets and pellets for fluidized beds, but the tablets are coated in bottom spray The core of fluidized bed granulation is the spray system of liquid In almost all fluidized bed equipment, the function of the nozzle is twofold, namely granulation and coating The liquid is ejected through a hole at low pressure and atomized by the airflow This nozzle can produce smaller droplets, which is an advantage for pellets or pellets to coat, but with the increase of evaporation surface, small droplets rapidly change into solid concentrates during the forward movement, and the viscosity also increases In case of improper degree matching, some small droplets can not spread evenly when contacting with the surface of particles or pellets, forming incomplete film or uneven formation of particles and pellets, or even forming adhesive or coating material itself to dry into particles or pellets, resulting in unstable or unqualified product quality If the evaporation heat of the atomized solution is low, the problem will become more serious Some spray commonly used solvents and their evaporation heat are shown in tabular form Evaporation heat of common solvents In the top spray granulation and coating, the flow of particles and pellets is rather out of order, and the spray of adhesive or coating liquid is directed towards the evaporating medium The droplet itself is also very dry, with great loss, and the granulation and coating effect is poor The quality of the product is not stable enough So far, the granulation, pellet and coating process of a certain quantity are still carried out in the top spray mode This is because it has two advantages, one is that the production scale is much larger than other methods, the other is that the structure is relatively simple and the operation is convenient A production scale of top spray granulation and coating equipment requires only one nozzle and one pump Compared with the other two spray methods, there are usually multiple nozzles and pumps In this way, in the production operation, the former needs to consider much less variable parameters, and the cleaning cycle is also short.
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