Influence of particle machine particle length and its control measures

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  With the vigorous development of the modern animal husbandry and feed industry, the quality of feed demand is higher and higher, for pellet feed produced by granulating machine, grain length is an important quality assessment indicators, conform to the requirements, and tidy uniform length of grain is not only meet the needs of feed manufacturer sales, and is the need of user actual breeding, granule feedstuff is too long, too short or uneven is disadvantageous to animal feed. In actual production, the granulating mechanism of grain length, general requirements for 2 ~ 3 times the diameter of the particles, such as production ф diameter 3 mm size of granular material, its length is 6 ~ 9 mm, of course, according to the actual user needs and different varieties of feed, its length requirement may not be in this range. Therefore, in order to produce the length meets the requirements, or close to the requirement of feed particles, as far as possible to explore the effect on granulator particle length of some of the factors, and find the corresponding control measures, is advantageous to the production needs, for feed manufacturers, has the very vital significance. The author based on years of cuber design experience and site commissioning experience, will from the following several aspects to discuss the problem.

  1 The influence of pelletizer itself parameters

  Set granulator production for Q (kg/h), ring die diameter D (mm), the effective width ring mode to W (mm), ring die linear velocity V (m/s), the speed ring mode to n (r/min), the aperture ring mode to D (mm), ring mold opening rate of bits, hole number is n (a), pointing out the length of the particle when not cut off for L (mm), grain density for rho (kg/m3), then you can calculate the length of the cutting particles the size of material as follows: 

For the type, it is easy to analyze the influencing factors of pelletizer grain length L:

1.1The influence of the granulator production

By the formula can be seen that Q is proportional to the particle length L and output, in the case of other parameters constant, the higher yield, the longer the particles, the shorter the vice particles. Therefore, in order to achieve a specific particle length request, to adjust the output of granulator is one possible choice method, in the actual feed production, feed manufacturers did the same, sometimes even sacrifice a lot of production to meet the requirements of particle length, the problem will be mentioned in the discussion that follows.

1.2 The influence of ring die linear velocity or speed

Can be seen by the formula, the pellet length L and ring die linear velocity V or ring die speed n is inversely proportional to the feed speed under the condition of invariable output Q, the faster the speed of the ring die, the shorter the instantaneous extrusion particles, the longer the vice. For different sizes of pelletizer, ring die speed difference is very big, generally small granulating machine high speed, large granulating machine speed is low, but the ring die linear velocity control in a proper range, usually in 6 m/s ~ 9 m/s, to meet the needs of the granulating. When the ring die linear velocity is small, make particles of high quality, but make the particles may be longer than required, the linear velocity is too small will affect production at the same time; When ring mold high linear velocity, while beneficial to the improvement of the production, but make the particles may be shorter than required, at the same time the quality of the particles will become worse, and this requires feed manufacturers according to the different varieties to choose suits own ring die linear velocity, the method can be through changing the ratio of granulating machine drive system.

1.3 Ring die aperture, and the effects of opening rate  

Ring die aperture d affect grain length L not directly, it and open hole number N together to affect the length L, bits of the ring die opening rate, the size of the opening rate because bits of proportional to the square ring die diameter d and opening the product of the number N. Ring die opening rate, the greater the shorter mixture particles, the longer the vice particles. Ring die opening rate corresponding to different ring die aperture is different, such as ring die aperture is ф 1.8 mm ring die, opening rate is about 25%, the aperture ring mode to ф 5 mm ring die, opening rate is about 38%, generally is the larger the aperture, the higher the opening rate. In practical production, especially in the production of small diameter of granular materials, such as production ф 1.8 mm of shrimp, some users complain about making particles is too long, because small aperture corresponding ring die opening rate is low, one of the solution is available to sacrifice part of the way to implement of production, or use a section on by improving the ring die of linear velocity method, another method and adjust the cutting knife, etc., which will be discussed in the following content.

1.4 Ring die inside diameter, ring die effective width and the influence of particle density

For a granulating machine, ring die inner diameter D, ring die effective width W is relatively fixed parameter, generally will not change, the user is not easy to change, so their influence is not discussed here. Raw material of the particle density and granulating, and ring die on compression ratio, compression ratio, the greater the produced particles of the solid, dense, but for general product, particle density difference is not large, so the grain density is not a main influence parameters, there will no longer be discussed too much. In general for the same kind of pelletizing raw material, make the grain density, the greater the shorter length of particles.