Mixing—the most important part of premix feed processing
In order to obtain satisfactory quality pre-mixed feed, in addition to a mixer whose structure and technical parameters meet the technological requirements, reasonable arrangement of the front and rear procedures and reasonable use of the mixer itself are important conditions. In addition, the choice of carrier diluent, good charging of the animal feed mixing equipment, reasonable operation sequence and proper control of the mixing time are also necessary conditions.
1. The choice of carrier diluent
The various additives that need to be diluted are usually very fine, so choose a thinner with a particle size and density close to it. Suitable diluents or carriers include commonly used feed ingredients such as soy flour, wheat flour, defatted rice bran and the like. Generally, materials with fine particle size, no dust, and affinity for the active ingredients in the additives are selected as diluents or carriers.
If the diluent or carrier is selected properly, the finished product does not need to be shipped. If the active ingredient in the additive is not concentrated, there is no need to use a binder. If the pre-mixed product needs to be transported over long distances, grease should be used. The biggest disadvantage of using grease is that a part of the active ingredients of the additives stay on the blades of the feed mixer and affect the cleaning.
2. Feeding of the horizontal animal feed mixer
The order of adding various ingredients depends on the form of the mixer machine for animal feed, the general order is as follows:
(1) First send 80% of the diluent or carrier into the animal feed mill mixer;
(2) Spread the weighed active ingredient on the diluent or carrier. Some devices are inconvenient to place manually. The active ingredient can be fed in by a general mechanical method;
(3) Then feed the remaining 20% diluent or carrier.
3. Eliminate or reduce the storage and transportation process of premix after mixing.
During the material transportation process, due to the effects of gravity, wind, centrifugal force, friction, etc., the uniformly mixed materials change greatly. The longer the transportation distance and the greater the drop, the more severe the classification. Therefore, it is best to pack the mixed materials directly into bags to avoid or minimize the transportation and drop of the mixed materials, and do not use screw conveyors or bucket elevators as much as possible. The height of the silo should not be too high to reduce or eliminate Separation or classification of mixtures.
For each batch of mixtures, it must be clearly identifiable, and the packaging bags must be clearly marked. It is best to use colored symbols or labels to distinguish them.
4. Reasonable use of the animal cattle poultry cow fish feed mixer
(1) Suitable loading
Regardless of the type of feed mixers, proper charging is a prerequisite for the mixer to work normally and obtain the expected results. If the material is loaded too much, on the one hand, the mixer will be overloaded. More importantly, too much material will affect the mixing process of the materials in the machine, which will cause the mixing quality to decrease; if the material is too small, the mixing will not be fully exerted. The efficiency of the mixing machine will also affect the mixing quality. Therefore, no matter what kind of mixer, the filling degree of the material should be effectively controlled, so as to ensure the normal operation of the high quality horizontal feed mixer and make the mixed feed meet the quality requirements.
For batch horizontal ribbon mixers, the full coefficient is generally 0.6 to 0.9, and the maximum material level cannot exceed the top surface of the rotor; the full coefficient of the double-shaft blade mixer is generally controlled at 0.6 to 0.85.
(2) Correct mixing time
For batch mixers, the determination of mixing time is very important for mixing quality. If the mixing time is too short, the materials will be discharged without being fully mixed in the mixer, and the mixing quality cannot be guaranteed; if the mixing time is too long, the materials will be over-mixed in the mixer and cause separation, which will also affect the quality and can Increase in consumption.
The determination of mixing time depends on the mixing speed of the mixer, which is mainly determined by the model of the mixer. Such as horizontal ribbon mixer, usually 3 to 5 minutes per batch, its length depends on the type and nature of the raw materials, such as moisture content, particle size, fat content, etc.; the mixing time of the biaxial blade mixer is less than 2 minutes per batch; For the tumbler mixer, because of its slow mixing effect, a longer mixing period is required.
(3) Reasonable operation sequence
In the order of feeding, generally the components with a large proportion are added first or most of them are added to the machine, and then a small amount and a small amount of components are placed on the material. Among various materials, those with larger particle size are generally added to the mixer first; while those with smaller particle size are added later. There are also differences in the density of materials. When there is a big difference, the materials with low density are generally added first, and then the materials with high density are added.
(4) Try to avoid separation
①Any powder with good fluidity has a tendency to separate. There are 3 reasons for separation:
★When the material falls on a pile, the larger particles fall under the pile due to the larger inertia, and the smaller particles with smaller inertia may be embedded in the cracks on the pile;
★When the material is vibrated, the smaller particles have a tendency to move to the bottom, while the larger particles have a tendency to move to the top;
★When the mixture is blown or fluidized, with the difference in particle size and density, separation occurs accordingly.
②To avoid separation, the following methods should be adopted:
★Strive to be close to the particle size of the various components of the mixture; or use the method of adding liquid to avoid separation.
★Master the mixing time and do not over-mix. It is generally believed that the materials should be discharged before being nearly uniformly mixed, and the mixing should be completed during transportation or transit.
★Minimize the loading and unloading work after mixing. The less material falling, rolling or sliding, the better. The mixed storage bin should be as small as possible. The mixed transportation equipment is preferably a belt conveyor, and screw conveyors, bucket elevators and pneumatic conveying devices should not be used as much as possible.
★The grounding of the electric feed mixer and the addition of antistatic agents to the feed can reduce the separation of the mixture due to the adsorption of static electricity.
5. Frequently inspect and repair the drum feed powder mixer
As far as the horizontal ribbon mixer is concerned, after a period of use, the wear, damage and deformation of the ribbon, and the increase of the gap between the ribbon and the mixer shell will greatly affect the uniformity of mixing. In addition, the leakage of the discharge door is also one of the important factors affecting the performance of the mixer. In order to ensure the quality of feed products, the running performance of the animal fodder mixer machine should be tested regularly, and maintenance should be carried out every six months.
To sum up, the mixing process in the additive premix feed production process is actually a very complicated process. In actual production, sufficient attention must be paid. The quality control of the production process involves many aspects, from raw material selection, The selection of machinery and animal feed premix mixer equipment, the use of operations, the best process parameters of the mixing process, the sequence of the mixing process, and the operation of personnel. It constitutes a variety of factors that affect the final quality of premix products. Only by comprehensively considering all aspects that affect product quality can we ensure the production of premix products that meet product quality standards and meet the needs of animal growth.
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