A, crushing process

Shrimp feed ingredients crushed is a basic processing technology, crushing particle size should be 40-60 mesh or more. Li Aijie (1990) study that: 40-100 mesh sieve over the peanut cake flour, its protein digestibility is not significantly different. From the processing of energy consumption considerations, the energy consumption used in the hammer mill to reach 100 mesh than 40 mesh more than three times higher. Therefore, the fineness of the raw material is not less than 40 mesh, but the finer the crushing fineness, the better the water resistance of the pressed particles. In addition, it can also improve the mixing uniformity of feed, improve the quality of pellet feed pressing, as well as facilitate the contact of digestive enzymes with the feed to promote digestion and other functions.

Raw material crushing needs two processes, the first is coarse crushing, such as peanut cake and shrimp head shells, need to use 400-type hammer bean cake crusher, with sieve holes for 3 mm sieve, the raw material is crushed into coarse powder; the second is fine crushing, can be used in ultra-micro pulverizer or 50-type hammer crusher, the latter should be equipped with sieve holes for 0.5 mm sieve. Crushing must reach all through 40 mesh, 80% through 60 mesh requirements.

? Second, the ingredients process

Raw materials must be cleaned up before crushing, such as hammer chips, paper, wood, stone and other debris. Before the second crushing according to the proportion of the formula should be ingredients such as peanut cake powder, fish meal, hemoglobin powder, squid powder, etc. to mix. Crushed into more than 40 mesh powder, and then add standard flour, additives, etc. for mixing, so that the mixture is uniform, the coefficient of variation is not greater than 10%.

? Third, the tempering process

The crushed raw materials are generally moisture content of about 13%, the material is not easy to soften the granulation and pasting, on the pressure granulation and water resistance has an impact on the water, so the appropriate addition of moisture is to ensure that the powder bonding and starch pasting is another important condition. First of all, should be in the mixing, with a high-pressure pump spray water for a few minutes to achieve the powder moisture content of about 18%; followed by steam added. So that the moisture content is uniform, the material to reach the softening requirements. After the addition of steam, the material temperature is rapidly increased, prolonging the material paste time, starch paste fully, the working temperature of the die is reduced accordingly, improve the service life of the die, the material is processed by the steam temperature reaches 90-105 ℃, the processing effect is good, the steam pressure should be controlled between 4-15 kg / cm2 and Keep stable.

? The produced feed is dark brown with smooth surface. The length of the particles is consistent, the flavor is delicious, and the enticement is strong. If the temperature is below 80℃ after steam treatment. The particles are yellowish-white, powdery, with poor water resistance, and the shrimp are anorexic, because the feed is not completely pasted and cooked. Like sandwich board. When the discharge temperature exceeds 105 ℃, the granulation becomes black, good adhesion, but the nutrients are damaged, shrimp anorexia, and it is not easy to digest. The amount of moisture added to the moisture content of the material should be made about 17%-18%. Generally in the steam added after tempering, in the host to take the material in the hole, hand held into a ball, a little vibration, to be able to crack can be. Moisture is too little when the paste is slow, granulation current, particles are not neat, the yield is reduced; too much moisture is easy to make the pellet machine slippery, clogging mold holes. The actual operation of the steam added to the pellet machine does not slip, do not block the mold hole for the limit.

Shrimp feed host tempering device is different from livestock feed, should be increased and lengthened, usually using two tempering device, you can make the steam uniformly penetrate the material to achieve the purpose of starch softening, pasting. Host ring die with a long time, the inner diameter of wear, flared mouth deformation, affecting the normal granulation or clogging mold holes. The ring mold should be disassembled, and the powder of the mold hole should be beaten out and dipped in oil to make the inner wall of the hole smooth; if the inner wall of the ring mold is worn seriously, the inner wall should be polished and the flare should be re-processed. Imported machinery is best to use the original ring mold. Shrimp feed particles with a diameter of 2-25 cm is good. Young shrimp material after crushing processed into 0.3-0.6 mm micro-particles.

Fourth, drying

After the host pressure out of the granules, high moisture, need to be dried, available electric drying or steam drying. Its role is to reduce the moisture content of the pellets, moisture content is usually below 10%, to ensure that the feed does not deteriorate in more than 2 months; followed by the promotion of re-pasteurization, to play the role of maturing, increase the bonding of the pellets.

Electric dryer temperature is generally required to 90 ℃ is appropriate, pellets through the time of about 20 minutes. If more than 90 ℃ or drying time is too long, granules have the possibility of burning, vitamin destruction, affecting the shrimp's liking and feed full-value. Steam drying temperature can be relatively increased to 105 ℃.

Fifth, cooling

Pellets of cooling is usually carried out in the cooling tower, the use of extractor fans, sucking in a large amount of cold air to take away the tower pellets of heat and part of the water, to be pellets down to room temperature ± 1 ℃ or so, for packaging.

If the granule is not processed by the dryer directly into the cooling tower, the surface of the granule due to the first internal rapid cooling and dehydration, the surface of a large number of small cracks and to the depth of the expansion, even if the paste effect of the fine granular material will produce the above phenomenon is also very good. When feeding, after soaking in water, it will be decomposed into a number of clusters along the cracks, making the water resistance worse, if dried, the above phenomenon will be much less. The moisture of the granule is 17%-18% when it comes out of the granulator, and the moisture content is 12%-13% after drying, and it can be 10%-11% after cooling.