After mixing the powder feed by granulating, and can make the nutrition and edible quality of feed and so on various aspects have different degrees of improvement and improve. Granulating applies not only to livestock and poultry feed, more suitable for aquatic products and special feed. Due to the different varieties of feed raw materials, components, finished product size is different, the granulating equipment performance and structure parameters also have different requirements. Granulating process are generally equipped with granulating, cooling, the broken and grading equipment, some still equipped with oil paint system. The above several kinds of equipment selection principle is as follows:

1, the granulator feed mills use granulating machine has two kinds of ring die peace die. Flat die is more suitable for granulating of roughage, so only the ring die pelletizing machine instructions. Because the ring die pelletizer, similar to the working principle of model selection for its performance evaluation mainly from the rationality of structure design, operating convenience, the selection of structure parameters, the processing method, manufacture level, parts selection, supply channels and control functions to several aspects, such as comprehensive consideration.

2, after the cooler to granulating product can maintain good storage performance, is indispensable to the granulating process. After a long time, granulating cooling using fault current cooling, although can satisfy the use requirement, cooling particle temperature is less than 7 oc but if they would be easy to reach the standard when operating. Therefore, recently appeared the counterflow cooler is a cooling principle of reasonable models, due to convection heat exchange system is the most perfect and reasonable.

3 pieces, crushed grain machine can save power consumption, improve digestion and absorption rate of livestock and poultry. Now, almost all the broken machine adopts roll pieces, its performance through the analysis of the structure rationality, the structure of the machine parameters and process parameters, the level of processing to assess. Roller diameter pressure big, easy to break. Roller tooth form has two kinds, one kind is crossed helical gear, and back to the front as appropriate, unfavorable and overmuch, number of reducing flour yield; With the second type is straight helical combination, this combination disposition rate also is less, but these two kinds of tooth arrangement can satisfy the use requirement, flour extraction rate should be controlled within 3%. But starting from the actual use, it is very important to adjust the distance of two rollers, otherwise work under two roller distance range, products are not uniform, can be in in regulating handwheel is equipped with the markings for operation. Also must pay attention to the broken machine model selection of the imported size, to export perfectly match with cooler, otherwise will increase flour yield.

4, after sizing screen the broken material part to remove the powder after classification, to ensure the small particles of material with pure, make the feeding effect is best. Existing sizing screen mainly sizing screen, rotary vibration sieve, both can achieve better effect. Vibration sizing screen should be based on the properties of the material, flow to adjust the amplitude of the sieve body, in order to achieve the best effect. Rotary vibrating screen by screen surface distance is longer, so the sizing effect is better, and it is one of the commonly used equipment. In a word, these two types of models can meet the use requirements, grading efficiency can reach 98% ~ 99%.

5, curing aging is to improve feed gelatinization degree, improve the pellet feed water resistance by setting process, at the same time can improve granulating edible quality and performance. The curing process is still in its infancy. At present, the selected with the steam curing process after adding curing stabilizer system and jacketed heat preservation device, keep the material temperature at 80 oc to 90 oc particles within the machine can keep 20 ~ 40 min (adjustable), can make particles of starch pasting or reticulate structure, which can satisfy the requirement of resistance to water more than 6 min.

6, extrusion (inflation), extrusion machine, extrusion expander and extrusion machine working principle, main structure parameters and technological parameters is large, such as screw, compression ratio of 1.05 ~ 1.2:1 interior stability for 120 oc to 130 oc extruding chamber pressure is 9.8 x 10-5-4.9 x 10-6 pa. The damage of harmful factors in 80% ~ 90%, starch gelatinization degree of 85% ~ 90%.

Another screw or whether the material of alloy steel, a screw is reasonable, advanced processing means, how the performance after heat treatment, has a direct relationship between these parameters and the use effect, can not be ignored, must understand.