Granulation coating machine manufacturer

　　1Application scope of multifunctional granulation and coating machine

This machine is clean, efficient, safe to operate, and easy to clean. It is suitable for laboratory and pilot production use, and is suitable for surface coating of various shapes of tablets, pills, candies, and other products in industries such as pharmaceuticals, chemicals, and food.

　　2、 Product characteristics of multifunctional granulation and coating machine

1. The coating machine is convenient for feeding and has high efficiency.

2. Easy to clean, the coating pot can be disassembled by itself.

3. The coating machine uses imported spray guns, which are easy to operate and master, with flexible control of process requirements. The atomization effect is good, and the liquid medicine is sprayed evenly.

4. The half hole design and pot body design of the machine help reduce wear on the tablet core and coating film, improve the yield rate, and thus balance drying efficiency and protection of the coating film.

5. This machine can be equipped with 1-2 different specifications of pots as needed to solve the problems of laboratory variety, limited quantity, and high raw material prices. The replaceable pot body can better meet the diverse needs of customers.

　　3、 Product Description

This product is a new type of equipment that integrates strong electricity, weak electricity, hydraulic and pneumatic functions, and transforms the original ordinary sugar coating machine. It is mainly composed of host (raw sugar coating machine), controllable normal temperature hot air system, automatic liquid supply and air supply spray system, etc.

In the process of fluidized bed granulation or pellet making and coating, the spray method should be selected according to the material performance and planned product quality. At present, there are three methods of fluidized bed spray, namely top spray, tangent spray and bottom spray, as shown in Figure 15-21.

(1) Top spray

Most products that coalesce in fluidization are produced using this method, and the particles produced are characterized by porous surfaces and interstitial voids, with a low bulk density. It is an effective method to increase the solubility of insoluble drugs because particles or pellets are prone to absorbing liquids and disintegrate quickly, such as in the drying and granulation of traditional Chinese medicine extracts.

(2) Tangent spray

It utilizes the centrifugal force generated by the rotation of the turntable to achieve high-strength mixing effect, combined with the drying efficiency of the fluidized bed, thereby producing products with high bulk density but still a small amount of gaps and voids. The particles have high hardness, are not easy to break, and are close to spherical shape, which is a common method for preparing microspheres.

(3) Bottom end spray

The bottom end spray is to set the nozzle in the guide tube at the center of the airflow distribution plate, and fluidizing particles, pellets or tablets receive adhesive or coating solution in the guide tube. It is currently the commonly used method of coating microspheres, with the advantages of high coating efficiency and low adhesion of microspheres. Xinyi Special has developed an improved fluidized bed that can adjust the internal and external air volume of the draft tube online, and can clean the spray device online, greatly improving the controllability of the fluidized bed pellet coating.

The above three spray methods can be used for the preparation and coating of particles and pellets in the fluidized bed, while the tablets are coated in the bottom spray type. The core of fluidized-bed granulation and coating process is the liquid spray system. In almost all fluidized-bed equipment, the role of nozzle is dual, namely granulation and coating. The liquid is ejected through an orifice under low pressure and atomized by the air flow. This nozzle can produce small droplets, which is an advantage for the coating of particles or pellets, but it also brings about an increase in the evaporation surface. The small droplets quickly transform into solid concentrate in the process of moving forward, and their viscosity also increases. If the spray speed, solution concentration and fluidization temperature are not matched properly, some small droplets cannot spread evenly when contacting the surface of particles or pellets, forming incomplete films or uneven forming of particles and pellets, or even forming adhesives or coating materials drying into particles or pellets, resulting in unstable or unstable product quality Qualified. If the solvent evaporation heat of the atomized solution is low, this problem will become more severe.

　　Evaporation heat of common solvents

In the top type spray granulation and coating, the flow of particles and pellets is disorderly, and the spraying direction of adhesive or coating liquid is toward the evaporation medium, so the liquid drops are also seriously dried, with large losses, poor granulation and coating effects, and unstable product quality. Although this is the case, a considerable number of granulation, pill making, and coating processes are still carried out by top type spray, which has two advantages: one is that the production scale is far larger than other methods, and the other is that the structure is relatively simple and easy to operate. The top spray granulation and coating equipment of one production scale only needs one nozzle and one pump. In contrast, the other two spray methods generally use multiple nozzles and pumps. In this way, the former requires much fewer variable parameters to consider during production operations, and the cleaning cycle is also shorter.

　 4、 Main process parameters
In the process of fluidized bed granulation or pellet making, the growth of particles or pellets can be divided into three stages: nucleation, layering, and pellet formation. If the process parameters are not reasonable, particles or pellets may merge into large aggregates, which should be avoided in the granulation and pellet making process. The effective way to avoid this is to optimize and determine the main process parameters.

(1) Drying rate is one of the important factors affecting particle properties. High inlet air temperature and fast drying speed can use faster spray rate and reduce the change of drying capacity caused by the change of ambient air humidity. However, when the high-temperature air flow is introduced, the solvent directly evaporated in the spray liquid increases, the adhesive solution wetting and penetrating the powder decreases relatively, and the density of the finished product decreases, which is fragile and the particle size becomes smaller. On the contrary, when the temperature is too low, the adhesive solution evaporates too slowly, and soon reaches or exceeds the critical liquid content control point, which destroys the fluidization state, forms a larger condensate, and leads to product rework.

(2) The static bed depth (h) refers to the height occupied by the material after being loaded into the bed, and its size depends on the production capacity of the mechanical design. In general, when it is ≥ 150mm, it is difficult to achieve an appropriate fluidized state due to being too small, or the airflow directly penetrates the material layer and cannot form a fluidized state. When confirming the static bed depth, it is necessary to consider the characteristics of the material, such as density, powder thickness, hydrophilicity, and lipophilicity.

(3) In general, the airflow velocity is determined based on the static bed depth and material properties, and an appropriate airflow velocity is beneficial for establishing a good fluidization state.

(4) The spraying rate is selected based on the material loading and properties, as well as the temperature of the introduced airflow, to bring the material close to the critical liquid content and maintain a good moist state. It also depends on the good dynamic balance between spray factors, drying factors and fluidization factors in the whole process of granulation and pills.

In the fluidized bed coating process, the impact of spray rate is more complex than that of granulation and pelletizing processes. In the granulation and pill process, the spraying rate is generally limited only by the drying capacity, while in the coating process, the spraying rate is not only limited by the drying capacity, but also more likely to be affected by the properties of the sprayed liquid and the time required for coating. In the coating process, it is required to introduce air flow at a high temperature to meet the needs of water or solvent evaporation. Small droplets can move forward for as short a distance as possible to come into contact with particles and pills. Only under the above conditions can the coated product maintain the reproducibility of drug release rate. In addition, the particles and pills must pass through the coating area quickly, or they will become aggregates due to local over wetting. Therefore, if the top spray is used, there will be some shortcomings, because the transport distance of the droplets is too long. Two other spray devices can be selected, and multiple nozzles are preferred, because the dispersion of droplets is greater than that of a single nozzle, which causes less local over wetting.