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Technical factors of feed production caused by mould

The granulating mechanism is quick and effective, and the filter with special holes is designed for careful screening. The friction filter rod can crush the solid particles, which is widely used in pharmaceutical, chemical and food industries.This machine can replace the swing granulator and is a new generation granulator.In the pelletizing production of granulator, there will sometimes be abnormal appearance of granules, for inexperienced or new feed manufacturers, sometimes can not find the crux of the problem.The following seven common abnormal appearance of the granule produced reasons and the improvement methods are introduced to you, for the feed production for comparison reference.

1. The granular material is bent and has many cracks on one side

This phenomenon usually occurs when particles leave the ring mold.In production, when the cutter is located far away from the surface of the ring die and the blade is blunt, the particles are knocked or torn by the cutter rather than cut off when extruding from the die hole. At this time, some particles are bent to one side and many cracks appear on the other side.The particles tend to break from these cracks as they enter the cooler for cooling or transportation, resulting in too much pellet powder produced.

Improvement methods:

A) increase the compression force of ring mould on feed, that is, increase the compression ratio of ring mould, so as to increase the density and hardness of granular material;

B) pulverize the feed raw materials more finely. If molasses or fat are added, the distribution uniformity of molasses or fat should be improved and the added amount should be controlled to improve the compactness of granule and prevent the feed from being soft;

C) adjust the distance of the cutting knife from the surface of the ring mold, usually the distance between the blade and the outside surface of the ring mold is not greater than the diameter value of feed particles produced, or change to use a sharp cutting blade. Thin blade can also be used for particles of small diameter, and the thin blade can be closely produced on the surface of the ring mold.

D) the use of bindlike granulation AIDS helps to improve the cohesion within particles.

2. Horizontal cracks cross the whole granule

Similar to the phenomenon in case 1, the crack occurs on the cross-section of particles, but the particles do not bend.This may occur when a fluffy feed containing more fiber is granulated.This kind of granular material is usually when the feed is squeezed into the grain hole of the circular mould, because it contains the fiber with a longer diameter than the hole, when the grain is extruded, the expansion of the fiber makes the granule produce a cross-section crack on the cross section, producing the fir bark shape of the feed.

Improvement methods:

Increasing the compression force of annular mould to feed, that is, increasing the compression ratio of annular mould;

Control fiber comminution fineness, its maximum length can not exceed one third of particle size;

Reduce the output to reduce the speed of feed passing through the mold hole and increase the compactness;

Longer quality adjustment time, use multilayer or caldron type quality regulator;

When the powder is too moist or contains urea, it is also possible to produce fir bark like feed appearance, the added water and urea content should be controlled.

3. Vertical cracks are produced in granular materials

Some feed formulations contain fluffy and slightly elastic raw materials, which will absorb water and expand when being quenched by the tuner. After being compressed by the circular mould, the raw materials will spring apart due to the action of water and the elasticity of the raw materials themselves, resulting in vertical cracks.

Improvement methods:

Change the formula, but this may increase the cost of raw materials;To control the quality of the steam used in tempering and to minimize the amount of added water by using more saturated dry steam;Reduce the yield or increase the effective length of the die hole, so as to increase the time of the feed in the die hole;Adding a binder also helps to reduce the occurrence of vertical cracks.

4. The granular material produces radiant cracks from a source point

This kind of appearance that large particles of raw material is contained in grain, these large particles on raw materials, it is difficult to fully absorb moisture in the water and heat, is not as easy as other thinner material softening, and during cooling, due to the different degree of softening, lead to the difference of shrinkage, so as to produce radial crack, makes the pulverization rate increase.

Improvement methods:

The thickness and evenness of powdery feed raw materials should be properly controlled, so that all the raw materials can be fully and uniformly softened.

5. Uneven surface of granular material

This situation lies in that the powder used for granulating contains large particle raw materials that have not been crushed or semi-crushed. Due to insufficient softening during the tempering process, the particles are hard and large, and cannot be well combined with other raw materials when passing through the mold hole of granulator, which makes the particles appear uneven.Another case may be that the tempered material is mixed with steam bubble, which makes the feed produce air bubble in the process of compacting into particles. When the particles are extruded to the circular mould, the bubble will burst due to the pressure change and the bump phenomenon will occur on the surface of particles.This can happen to any feed containing fiber.

Improvement methods:

Proper control of the size of powdery feed so that all ingredients can be fully softened in the conditioning;For raw materials with more fiber, do not add too much steam into this formula because it is easy to inclusion steam bubbles.

6. Whisker granules

When in the production of granular material, if join the steam of too much, too much steam will accumulations in fiber or powder, particles in extrusion ring die, due to the pressure of dramatic change make particles burst cut the fibre or granular materials convex surface, forming a prick the hand whiskers, especially in the production of high starch and fiber content of the feed, the use of steam, the more the more serious.

Improvement methods:

Good quality.When the high-starch, high-fiber feed is granulated, the low-pressure steam (0.1-0.2mpa) should be used so that the water and heat in the steam can be fully released for the feed absorption.If the steam pressure is too high, or after the pressure reducing valve downstream piping distance conditioning device is too short, generally should be greater than 4.5 m, the steam will not necessarily good release the moisture and heat, so some of the steam accumulations of feed raw materials, after quenched and tempered when granulating causes described above whiskers particle effects, anyhow should pay special attention to the steam pressure control and pressure reducing valve installation position is correct.

7. Individual particles or inter-individual particles have different colors, commonly known as "flower material"

This situation is relatively common in the production of aquatic feed, which mainly shows that the color of individual particles extruded from circular mould is darker or lighter than that of other normal particles, or the surface color of individual particles is inconsistent, thus affecting the appearance quality of the whole batch of feed.

The reasons for this phenomenon are as follows:

A) due to the complexity of aquatic feed formula ingredients, raw material variety, the relatively small amount and some ingredients, raw materials mixed in, if the mixing machine mixing effect is not ideal, it is difficult to ensure that raw material of mixed into the granulator is uniform, thus in the process of adjusting quality and granulating, the moisture, temperature and pressure, under the function of physical and chemical changes in raw materials, color change leads to different components of the raw material, produce "flower", this kind of situation in the feed formulation containing raw material change color to the change of temperature and moisture sensitive when more outstanding.

B) inconsistent moisture content of raw materials used for granulation.In the production process of aquatic feed, in order to make up for the loss of moisture of raw material after ultra-fine grinding, a certain amount of water should be added to the mixing machine, which is then transferred to the conditioner.Some feed manufacturers are simple in the process, directly pour a certain amount of water in the mixer, rather than using a special sprinkler evenly injection, so it is difficult to make the feed after mixing evenly distributed water.When this mixture of raw materials enters the quenching machine, since it is impossible for the conditioner to further distribute the water evenly in a short time, under the action of steam, the curing effect of all parts of the feed after the quenching is inconsistent, and the color change after granulation is inconsistent.

C) there is recycled material in the silo for repeated granulation.After granulating of grain after cooling and screening, to become a finished product, after the screening of fine powder or granule material often enter the granulating technological process in, usually into the mixer or DaiZhi grain warehouse, because the material is a new conditioning and granulating, after quenched and tempered if uneven or inclusions and other raw materials mixed with small particles of material back to the machine, for some feed formula, sometimes produce "flower".

D) the inner surface finish of the circular mould aperture is inconsistent.Due to the inconsistency in the finish of the die hole, the resistance and extrusion pressure of the particles during extrusion are different, and the color change is inconsistent.In addition, some annular model holes have burrs on the wall, and particles scratch the surface during extrusion, resulting in different color surface of individual particles.

For the four reasons listed above, it is clear that the improved method is to control the mixing uniformity of the components in the formula and the mixing uniformity of the added water.Improve the quality control, control the tempering temperature when necessary, and adopt a lower tempering temperature to reduce the color change;Control the machine material. For the formula easy to produce "flower material", try not to use the machine material for direct granulation.Adopt quality guaranteed ring mold, control the finish of the mold hole, and when necessary, sand the mold hole before use.

In summary, seven representative manifestations of abnormal appearance of granules in feed production are discussed above, and some abnormal appearance of granules are not discussed here because they are not representative.From the above discussion, it can be seen that the causes of these phenomena are various, and they are not completely isolated from each other. This requires us to analyze and grasp the key points of these problems before we can solve them.