During the process of fish feed pellet production, it is vital that fish feed extruders can produce pellets normally and safely because pellet preparation totally depends on the pellet-making machine. As one of the primary key equipment for feed enterprises or fish farmers, the good running of fish feed extruder pelleting machines directly influences the economic benefits of feed plants. However, in actual production, it is not difficult for the extruder to be blocked before products are expelled from the die hole, causing the common pelletizer blocking phenomenon.
Through the on-site analysis of multiple equipment and multiple materials, in fact, the blockage reasons for the fish feed extruder machine are nothing more than several following situations:
²Inappropriate gap of the extruder screw and puffing chamber
In the process of extruding, raw materials are transported from the feeding hole to the whole extruder chamber via a screw, so the clearance between the extruder screw and puffing chamber is very important for fish feed making. 
In order to reduce the possibility of the clogged phenomenon, in the actual production, the operating personnel should pay attention to adjusting the clearance between the screw and puffing chamber on the basis of the best status formed by the compression roller and environment during regulation, and according to tests, the lower gap is about 0.5mm-1mm while the upper gap is around 1mm-1.5mm, and keeping the right-and-left gap basically the same is ok. For achieving this point, it is the experience and adjusting hand feeling of granulating workers that seems quite important.
The influence of steam
In general, the major elements of the most ideal production condition in the production process of pellet fish feed contain the suitable raw material and water content, the excellent steam quality, and the sufficient hardening and tempering time. Using dry saturated steam for granulation properly can help to efficiently increase the yield of fish feed extruders and improve the quality of fish feed pellets at the same time. Therefore, to ensure high-quality and high-yield pellets, granulating workers also need to make sure the quality of dry saturated steam enters the conditioner of the extruder machine, except that each driving part of the feed pellet extruder machine runs well. The appropriate saturated steam can play a part in softening and lubrication in the process of pelleting, which can promote the rate of production, lower the friction heat energy, and prolong the service life of the fish feed machine. In the meantime, it also has the ability to bring down power consumption and expedite the jelling of starch and the cementing of fiber materials. Besides, the saturated steam can increase the shaping rate of feed pellets and decrease powder materials, which makes materials with smooth and tidy appearance, thereby enhancing the competitive power of fish feed pellets.
Poor steam quality makes material with too high water content when out of the conditioner, which is easy to causes the die hole to clog and slip when the raw materials enter into the pelleting chamber, leading to extruder blockage. The specific performances of blocking show as follows:
- The pressure of steam is not high enough and the water content ratio, making it easy for materials to absorb too much water, while when pressure is low, the temperature of materials in tempering is also low and the starch cannot be in good gelatinization, then the effect of pelleting would be poor.
- The pressure of steam is not stable (sometimes high and sometimes low), and the tempering situation of materials is also steady, which leads to the big current fluctuation of fish feed extruder machine and the uneven dry and thirst of materials, then easily results in the blockage of the machine in the normal manufacturing process.
Pelleting workers need to pay attention to steam pressure, conditioner, feeding volume, and other kinds of factors at any time, avoiding too high water content of material tempering caused by steam pressure and high moisture. In the meanwhile, for the purpose of reducing the times of machine blockage caused by steam quality, the boiler room needs to provide high-class and steady dry saturated vapor. Additionally, pelleting workers also need to keep a watchful eye on material water content after tempering at any moment by using a simple and easy way to discriminate, Here is the detailed method: catch a handful of materials out of conditioner and hold as clump, if the clump just scatters after loosening the grip, then that is appropriate.
T effect of tempering
As is well known, for pellet feed to meet the competitive demands of the market, suppliers must make sure the quality of fish feed pellets is excellent. Before pelleting, the tempering effect of materials is of great concern because it directly affects the production capacity and pellet quality of fish feed extruder machines. Especially, the stability in water of special-type aqua feed is also an important index, if materials cannot get enough tempering and ripening before pelleting, then the index of water stability would be hard to guarantee. This so-called tempering refers to the preprocessing of powdery material before pelleting, and the process of fully stirring and absorption of the granulated powder and the appropriate amount of steam within the conditioner.
Choosing tempering equipment in line with the technical requirements can make materials fully stir and mix with steam within the conditioner, achieving the effect of softening materials and pasting starch, beneficial to powder compacting and shaping and producing the products up to standard. The conditioner should have heat preservation, heating, and moistening functions for a long time, which can make sure materials fully meet the tempering requirements, improving the surface appearance and inner quality of pellet feed, and enhancing the feed stability in water.
