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Causes of 7 kinds of abnormal pellet materials and its improvement measures.
Author:RICHi Time:2016-06-03
Causes of 7 kinds of abnormal pellet materials and its improvement measures.
Feed pellet mill, high speed, good effect, special hole in the filter design, careful screening, the friction mesh bar to bar sieve broken solid particles, in the pharmaceutical, chemical and food industry widely used. This machine is a new generation of granule equipment. Sometimes in the granulator production of pellet feed pellets appearance is not normal, for lack of experience or new production of feed manufacturers for, sometimes can not find the crux of the problem lies in where. The following seven common abnormal appearance of the granular material causes and improvement measures introduced to everyone, for the production of feed in comparison with reference.
1, the particle material bending and one side presents many cracks
This phenomenon usually occurs when the particle material is away from the ring. In production, when the cutter location adjustment from ring die surface is farther and knife edge is blunt, the particle is extruded from the die hole is cut knife touched off or tearing rather than being cut off, when there is part of the granular material bending to one side and the other side presented many cracks. This granular material in the cooler cooling or transport process, often from these cracks at the fracture, resulting in the production of granular materials, too much powder.
Improvement measures:
A) increase the compression force of the feed, that is to increase the compression ratio of the ring mode, so as to increase the density and hardness of the granular material;
B) the feed particle more fine some, if you add molasses or fat should be improving molasses or fat dispersion evenness and control the adding amount, in order to improve the density of granular materials to prevent feed soft;
C) adjust the cutter from the ring mold surface distance, usually edge from the ring mold surface distance is no more than the production of feed particles diameter values, or replace the use of a sharp blade, for small diameter particles can also be the thin blade, and make a thin blade close ring die surface production;
D) using bond type granulation additives, help to improve the internal particle binding force.
2, the horizontal crack across the particle material
Similar to the phenomenon in the case 1, the crack occurs in the transverse section of the particle, but the particle is not bent. When the fluffy pellet will contain more fiber, it is possible that this occurs. The particles are often in the feed to squeeze into the ring die pelleting holes, due to the existence of longer than the diameter of fiber, when the particles after being squeezed out, due to fiber expansion effect of the particles on the cross section of the generated across the crack, resulting in fir bark like appearance of the feed.
The improvement lies in:
Increasing the compression force of the feed, that is to increase the compression ratio of the ring;
The maximum length of the control fiber can not exceed 1/3 of the particle size;
Reduce the output to reduce the speed of feed through the hole, increase the density;
The length of the quenching and tempering of the time, the use of multi layer conditioner or kettle type;
When powder when the moisture content is too high or containing urea, also may cause fir bark like appearance of the feed should be added water and urea content control.
3, the particle material to produce a vertical crack
In some feed formulations containing fluffy and mildly elastic material, this material in after conditioning conditioner will water swelling, in after compress granulation, due to the role of water and raw material itself has the elastic and elastic, produced a vertical crack.
The improvement lies in:
Increased time to change the formula, but it has the potential to increase the cost of raw materials; quality control of conditioning the use of steam, as far as possible the use of a saturated dry steam, so that the addition of water as far as possible to minimize the; reduce production or increase the effective length of the die hole, as far as possible the feed stranded in the mould hole; adding binder also helps to reduce the occurrence of vertical cracks.
4, the particle material from a source to generate radiation type cracks
This kind of appearance showed that the pellet containing large particles of raw materials, such large particles of raw materials in the quenched and tempered, it is difficult to fully absorb water vapor in the moisture and heat, unlike other thin material so easy to soften, and on cooling, due to different softening degree, resulting in shrinkage differences, so as to generate a radial crack, the powder increase the rate.
The improvement lies in:
Properly control the size and uniformity of powder feed ingredients, so that all of the raw materials can be fully uniform softening when the quenching and tempering.
5, the uneven surface of particles
This is used for granulating the powder containing no crushing or half broken large granule raw material, because in the quenching and tempering process failed to adequately soften, where particles are relatively hard and relatively large, through the die hole of the granulating machine cannot well and other materials combined with together, the particles is uneven. Another may be after quenching and tempering of the raw material is mixed with steam soak and steam bubble to make the feed in particles are pressed into the process of generating air bubbles, when the particles are extrusion ring die moment, due to changes in pressure lead to bubble burst and produce uneven phenomenon on the surface of the particles. Any fiber containing feed is likely to occur in such a situation.
The improvement lies in:
Properly control the thickness of the powder feed, thus in the quenched and tempered to all raw materials can fully softened; for containing more fiber raw materials, due to the inclusion of a steam bubble, so don't in the formulation of this join too much steam.
6, the whisker shaped particles material
When in the production of granular material, if the volume of steam added too much, too much steam will accumulation in fiber or powder and particles in the extrusion die ring, because of the dramatic changes in the pressure the burst of particles and the fiber or particulate material is a convex surface, formed a shaggy whiskers, especially in production of high starch and high fiber content in feed, the use of steam more, the situation is more serious.
The improvement lies in
Good quenching and tempering. When we will be high starch and high fiber content in feed pelleting, should use low-pressure steam (0.1-0.2Mpa), in order to let the steam moisture and heat can be fully released to the absorption of feed. If the steam pressure is too high, or pressure relief valve downstream line distance conditioner is too short, the general should be more than 4.5m, the steam will not be very good release out of the water and heat, so part of the steam accumulation in feed material after quenching and tempering, when granulation leads to surface of the whisker like particle effects, in short, should pay special attention to the steam pressure regulator and relief valve installation location is correct.
7, a single particle or individual particle color is not consistent, commonly known as "flower""
This situation is common in the production of aquatic feed, mainly for extrusion die ring from the individual particles of color in color than the other normal particles of deep or shallow, or of a single particle surface color is consistent, thus affecting the appearance quality of the whole batch of feed.
Anyway, for feed production in the abnormal appearance of the particles discussed above the seven has the representative manifestation, and some grains in the appearance of abnormal phenomena due to the absence of representative, here not listed on. From the above discussion, it is seen that the reasons resulting in these phenomena is in many aspects, between each other is not completely isolated, which requires us to when dealing with such problems in the practical work, should add to the analysis, grasp the key to solve the problem.