[FDSP Engineering Case]Extruding aqua feed production line
Raw material receiving, cleaning and coarse grinding process
The material enters the cleaning equipment through the feeding pit and the bucket elevator for impurities removing and magnetic separation, and then enters into the pre-grinding bins. After coarse grinding, the material enters into the dosing bins through the elevator and the rotary distributor to participate in the first batch of ingredients. The primary purpose of primary grinding is to reduce the size difference and variation range of the material, improve the working condition of the ultrafine grinding mill, improve the working efficiency of the ultrafine grinding mill, and guarantee the product quality stability.
First batching and mixing process
It is done by electronic batching scale which is precision measurement and stable matching. After that the ingredients into the mixer for the first time. For the first time batching and mixing is the pretreatment process of pulverizing, can reduce the variation of material particle size range, improve the working condition of grinder, improve grinding efficiency, guarantee the quality of the products.
Second grinding process
In the second grinding process, the material after the first mixing is lifted into the bins to be grinded, and then into the second grinding. After the second grinding process is completed, the raw material enters the rotary screener to clean the fine villi formed by the coarse fiber in the crushing process .
The second mixing process
The raw materials are put into the second mixing machine after the second batching. At the top of the secondary mixing machine is with a manual feeding port, which is used for adding trace additives. In the above of mixing machine, there are two liquid adding devices, which are respectively used for adding oil and water. In the secondary mixing process, all materials should be fully mixed with CV less than 5%. After the material is crushed and mixed for the second time, it enters into the later working procedure -- extruding process.
Conditioning and extruding process:
In the extruding process, the material are cooked for a period of time in the condition of high temperature, high humidity, high pressure. In this process the material changes drastically in the physical and chemical properties. From die extrusion of instantaneous pressure drop, moisture in the feed changes from the liquid into a gas, and puffed emanate from the feed, and forms extruded feed.
Coating, drying and cooling process
After the material is extruded by the extruder, the wet and soft particles (moisture in 25% ~ 30%) are formed. In order to reduce the breakage of the particles, it is advisable to use pneumatic conveying to convey the pellet into the dryer for drying, so that the moisture of the material is reduced to about 13%. After the material is dried, it is put into the external coating system. By coating the surface of pellet feed with oil, vitamins and flavoring agents, it can not only meet the energy demand of fish and reduce the loss of heat-sensitive substances in the processing process, but also improve the palatability of feed and reduce the powder content. After the material goes through the external coating system, it will be cooled.
Product classification and packaging process
The cooled material is elevated into the screener for classification. The material under the sieve of the lower layer of the screener is usually fine powder material, which is returned to the pre-extruding bins for reforming.The contents on the lower screen are finished products, which are directly entered into the finished product bins and then weighed and packed.
