Horizontal Twin-shaft paddle mixer (1)
Solid preparations of solid beverages, health food and drugs all need to mix the components of solid powder. The proportion of components in the formula can reach 80%-90%, and the proportion of components is less than 1%. The forms are powdery, granular and flaky. The material characteristics include easy-to-flow materials, viscous materials, easy-to-agglomerate materials, poor fluidity materials, etc. At present, the mixers widely used in the mixing process of solid powder in China include double cone mixers, V-type mixers, three-dimensional motion mixers, two-dimensional motion mixers, and square cone hopper mixers, all of which are gravity mixers.
These mixers have the problems of low mixing efficiency, long mixing time and inability to mix materials with large differences evenly at one time. Since there is no stirring paddle in the mixer, materials that are easy to agglomerate, have poor fluidity or viscosity cannot be mixed evenly at one time. Materials with large mixing ratio are often mixed evenly by light-on step-by-step or premixing, especially when mixing valuable drugs.
Compared with other mixers, the double-shaft paddle mixer has the characteristics of strong mixing capacity, fast speed, low energy consumption and wide application range. During the mixing operation of the double-shaft paddle mixer, It is not affected by the density, particle size, shape and the like of the material, and there will be no separation and classification. When the ratio between powders is as low as 1: 10000, or when the amount of liquid added reaches more than 20%, the mixing uniformity can be ensured, and the mixing process is soft and does not damage the original physical characteristics of the material. The coefficient of variation CV of the mixing uniformity is less than 5%, and the best can reach less than 3%. This equipment has been widely used in the feed industry, and the production lines of large and medium-sized feed production enterprises in China basically choose double-shaft paddle mixers. The average net mixing time was 142.2 s.The mixing uniformity is 95.61%, and the natural residue rate is 0.632%. However, there is no report of using this equipment in the field of food and drug. It may be that there are dead corners in the mixing paddle of the mixer, which makes it difficult to clean. To achieve the cleanliness required by GMP, manual cleaning is often required for a long time, which may not necessarily meet the requirements. Therefore, the advantage of fast mixing speed cannot be brought into play.
Other countries have improved the double-shaft paddle mixer. The stirring paddle can be pulled out of the bin body to clean, which solves the problem of cleaning dead corners and greatly shortens the cleaning time. After cleaning, it can still keep the sealed state by pushing back.
