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Evaluation of negative pressure bottom blown fluidized bed coating machine
From：Changzhou Jiafa Granulating Drying Equipment Co.,Ltd. Add Time：2018-5-11 9:21:19
Abstract: on the basis of the concept of fluidized bed coating technology, the purpose of the analysis of the medicinal negative pressure bottom spray fluidized bed coating machine in Jia hair company is to make the users of the pharmaceutical factory have a more systematic understanding of the bottom jet fluidized bed coating machine.
Key words: fluidized bed coating; medical negative pressure bottom jet fluidized bed coating machine; comment and analysis
One of the trend of drug development in the world is to slow and controlled-release drugs. Because of the immature technology and equipment in the last few years, the slow control and release of drugs have been developed slowly. However, in recent years, a variety of pellet (granule) coating equipment have been developed through the research and development of the coating technology and equipment of pellet (grain), and it also promotes the slow control and release in China. The continuous development of drugs, the bottom jet fluidized bed coating machine is one of the successful equipment. The author, starting with the concept of fluidized bed coating technology, evaluates the medicinal negative pressure bottom jet fluidized bed coating machine of Jia hair company. The purpose is to make this kind of equipment make greater contribution to the development and production of slow controlled release and other drugs in China, and also make the users of the medicine factory have a more systematic understanding of the bottom spray fluidized bed machine.
1. "bottom spray" from a fluidized bed coating technology
The fluidized bed coating is in the process of fluidization, all the particles are suspended in the fluidized gas flow, the surface is completely exposed, can spray various coating liquid, and carry on the heat and heat exchange. Among them, the fluidization state is determined by the characteristics of the fluidized material and the structure of the equipment. Because of the different technology, the fluidization state is different. There are three kinds of spray technology in three forms, such as the top spray, the bottom spray and the side spray. In order to make the film uniform and continuous, try to reduce the stroke of the droplet (that is, the distance of the droplet to the surface of the particle from the outlet of the nozzle), so as to reduce the spray drying effect of the hot air on the droplets, so that when the liquid drops to the surface of the coated particles, it can basically maintain its original characteristics to achieve uniformity, ideal spreading and coating film. The continuity. A comparison is made between the top, bottom and side spray fluidized beds.
(1) in the top blowout fluidized bed, the material groove is usually conical and the spray gun is at the highest level. The flow air flows through the bottom sieve into the material slot. With the increase of gas flow, the original stationary material is driven by the air flow, and the particles are accelerated by the air flow and pass through the nozzle, and the nozzle is ejected from the nozzle to attach to the irregular motion. The direction of the particle surface is opposite to the particle motion direction.
(2) the atomizer is set at the center of the bottom jet fluidized bed, and the circular guide tube is set in the center of the material bed with the expansion chamber. The distribution plate has a large opening rate in the direction of the guide tube, so as to meet most of the air flow, forming the flow pattern of the type fountain type. The powder accelerates from the air flow in the guide tube, and then leaves the guide. The cylinder enters the expansion chamber, and the wind speed drops sharply and the material falls into the ring gap area between the bed and the guide tube, so that the circulation makes the material highly dispersive.
(3) the side jet fluidized bed material tank is cylindrical with a variable speed turntable at the bottom. The turntable can be moved up and down to adjust the intake volume. The coating liquid is used to spray the atomizing nozzle on the wall of the material. The spray direction of the nozzle is in accordance with the direction of the particle flow, and the coating liquid is cut into the injection slot. The movement of particles in the trough is spiral, uniform and orderly, and three forces are synthesized.
For top spray, bottom spray and side spray, the three kinds of spray are characteristic in the fluidized bed coating. Compared with table 1, it can be seen that the bottom spray type belongs to the most suitable bed type of pellet (particle) coating. It
Characteristics of 2 bottom jet fluidized bed coating machine
The bottom spray fluidized bed coating was founded in 1959 by Dr. Dale Wurster of Wisconsin University. The spray fluidization and spray formed the state of the fountain, making the industrial coating become realistic. The wide application of the technology has yet to be compared to other forms. Its characteristics are:
(1) the direction of the spray is consistent with the direction of particle movement in the same direction, showing a fast, continuous and homogeneous feature.
(2) the coating liquid is an orderly movement of particles in the vicinity of the nozzle, so the droplet on the surface of the coated particles is very short, and it is easy to form a continuous and tight coating film, and the coating film is of good quality.
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