Classification of extruder
Classification of extruder
1. By functional characteristics
It can be divided into single-function extruder and multi-function extruder. Single-function extruder is simple in structure, parameters can`t be changed at will, it is specially designed for a single product, large limitations, poor adaptability (mostly small extruder). And multi-function extrusion function through the change of some parameters and parts such as screw, barrel, the replacement of die head, implement different requirements of length to diameter ratio, compression ratio, shape of die hole, hole area, screw rotation, the change of the process factors such as temperature, pressure, which can meet various demands, is suitable for the production of various products.
2. By processing method
It can be divided into dry expansion and wet expansion. Dry puffing is a kind of extruded puffing without water or external heating, which simply depends on the heat generated by the friction between the material and the extruder screw and the cylinder wall. Because soybeans contain a lot of oil, they lubricate well. Dry puffing machine has simple structure and low price, but it is difficult to operate, the extrusion temperature is not easy to control, the nutrition damage is large, and the energy consumption is large and the yield is low. With the development of extrusion technology, there are more and more types of processed materials, and the performance difference is also very big. Many materials have low oil content, low water content and poor fluidity, so they c
Inspection of pellet feed quality
The inspection of pellet feed quality mainly includes: forming rate, pulverization rate (durability), hardness, stability in water (it is required for aquatic feed). In addition, there is a certain requirement for the appearance of the quality of the pellet feed.
1. Forming rate.
The forming rate is the proportion of the particle amount and the total amount of the powder after it is pressed. It is a measure of feed formula, quenched and tempered, powder particle size, pressure model etc. comprehensive performance of an index. At the time of the test, we screened the size of a sieve with a diameter of 0.8 times the diameter of the sieve. Generally, the forming rate is required to reach above 95%. If it fails to reach this standard, the reason must be found out for improvement.
2. Pulverization rate (durability).
The pulverization rate (durability) indicates the solidity of the particles and their ability to withstand various handling and handling processes without being damaged. During the test, the pulverization rate was measured by a tester (chamber method). To get the sample of 500 grams passing through the sieve, the sample is in the box, spinning at 50 revolutions per minute for ten minutes, then pouring the sample over the weight, and the powder should be less than 5% qualified.
Hardness is the ability of a particle to withstand stress