The first section of the
Crushing is an operation that mechanically overcomes the cohesive force of a solid material to break it. The comminution of feed ingredients is one of the most important processes in the processing of feed. It is an important factor affecting feed quality, production, electricity consumption and processing costs. The power of the crusher is about 1/3 of the total power of the feed mill. The proportion of micro-pulverization energy consumption is greater, so how to rationally select advanced crushing equipment, design the best process route, and correctly use the crushing equipment is very important for feed production enterprises.
First, the purpose and requirements of the
Feed pulverization has a significant impact on the digestibility of the feed and the performance of the animal, and also has an important impact on the processing of the feed and the quality of the product. The suitable pulverization particle size can significantly improve the conversion rate of feed, reduce the excretion of animal feces, improve the production performance of animals, and facilitate the mixing, quenching, granulating and puffing of feed.
(1) Purpose of crushing
1. Increase the surface area of ​​the feed, which is conducive to the digestion and absorption of animals. Animal nutrition tests have shown that reducing particle size, improving digestion and absorption of dry matter, protein and energy, and reducing the ratio of meat to meat.
2. Improve and improve the processing properties of materials. By pulverizing, the particle size of the material can be substantially uniform, and the material classification after mixing is reduced. For trace elements and some small component materials, only the pulverization to a certain extent, to ensure that they have a sufficient number of particles, can meet the requirements of mixing uniformity; and for the granulation process, the particle size of the pulverized material must consider the pulverized particle size and pellet feed. The interaction, the particle size of the comminution will affect the durability of the granules and the stability of the aquatic feed in water.
(2) Crushing particle size requirements
There are different grain size requirements for different feeding objects and different feeding stages, and this requirement is quite different. In the feed processing process, the animal must first meet the basic requirements for particle size, in addition to other indicators.
1, the appropriate crushing size of pig feed
1) Piglet feed crushing particle size: The results of various studies show that the crushing particle size of the grain raw material in piglet feed is preferably 300-500. Among them, weaned piglets are 0 to 14 days after weaning, and 300 is appropriate. It is preferred to use 500 after 15 days after weaning.
2) Crushing particle size of fattening pig feed: Feed test shows that the grain size reduction will improve body weight gain and feed conversion rate, but in small particle size, pig gastrointestinal damage and keratinization will occur. Tests have shown that the suitable crushing size of growing and finishing pigs is between 600 and 500. Feeding fattening pigs after granulation with a small-sized feed reduced the dry matter in the manure by 27%.
3) The pulverized particle size of the sow feed, the appropriate pulverization particle size can also increase the feed intake and nutrient digestibility of the sow, and reduce the discharge of the sow feces. A large number of tests have shown that the smashing size of the sow feed is 400-500. Most suitable.
2, chicken feed crushing particle size requirements
Through a large number of comprehensive research results, the weight gain of chicken feeding small-grained feed is significantly higher than that of eating large-grain. The crushed grain size of the grain in the broiler feed is preferably from 700 to 900. Laying hens are not sensitive to the comminution of feed, and are generally controlled at 1000.
3, the requirements of the fish and shrimp feed on the crushing size
The particle size of the fish-fed feed recommended by the NRC (1993) fish nutrition requirement standard should be less than or equal to 0.5 mm. Generally, the pulverization requirements of the raw materials for the compound feed for fish are all passed through a 40-mesh sieve (0.425 mm sieve hole), and the 60-mesh sieve (0.250 mm sieve) has a sieve content of not more than 20%. The logarithmic geometric mean particle size of the fish feed should be below 200. China's aquatic product standards (SC2002-94) for the Chinese shrimp professional feed crushing particle size requirements are all through the 40 mesh sieve (0.425mm mesh), 60 mesh sieve (0.250mm mesh) sieve on the sieve is not more than 20%, the particle size in 200 or less. The requirements for squid and turtle feed are very fine. Generally, the larvae and juveniles require 98% of the 100 mesh sieves, and the average particle size is less than 100. The mash and the mash feeds are generally controlled by 98% of the 80 mesh sieve. The diameter is controlled below 150.
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