Puffing machine changes in the ups and downs of fish feed

Puffing machine changes in the ups and downs of fish feed

Due to the different processing technology and traditional pellet feed, the bulking material has more advantages than traditional pellet feed, and has been accepted by more and more farmers. The industry generally believes that the expansion of raw materials will gradually replace the traditional pellet feed and become the mainstream of the market, especially aquatic feed and pet feed. It is the difference between the two processing processes that determines that the bulking material has a greater advantage than the pelletized feed.

The processing technology of aquatic products is summarized as follows: raw material acceptance → cleaning → coarse crushing → weighing → mixing → fine crushing → weighing → mixing → storage → conveying → quenching → puffing → drying → sieving → liquid spraying → Cooling → storage → sieving → packaging.

The unique function of the extruder is to change the bulk density of the feed to make a floating, sinking or slow-falling fish feed. In North America, most fish feeds are made to float. Floating fish feed not only improves feed efficiency, but most importantly allows farmers to see the fish intake and reduce environmental pollution. The processing of floating fish feed requires the injection of steam and water. The material should contain 20% starch, which acts as a binder and energy substance. The expanded product should have a temperature of 125 to 138 ° C, 34 to 37 atmospheres (33 to 36 kg / cm 2 ), and 25% to 27% of water before the mold is released; after bulking, the bulk density should be 320 to 400 g / L, and the moisture content is 21%. twenty four%. This shows that when the swell is released from the mold, it will lose 3 to 4 percentage points of water. Just when the puff is released from the mold, the pressure suddenly releases, so that the superheated water becomes steam and the puffed water is lowered; this also causes many small bubbles, and the puffed feed can float. The fish feed is usually further dried (less than 10% moisture), which also enhances floating. The bulk density of 480g/L was identified as the turning point of the pellet feed float, which was lower than the float, higher than the sink. If necessary, the fish feed can also be used as a sinking feed with a puffing machine . When making a sinking feed, inject water into the modulator (without or with less steam), the ring mold should have 26 to 30 atmospheres (25 to 29 kg/cm2), and the bulk should contain 28% to 30% of water. It is 450 to 550 g/L, the temperature is 120 ° C, and the moisture is 26%. The wet ripening extruder uses a die with a venting port, and the dry puffing machine uses a secondary puffing die (Rokey and Huber, 1994), which can reduce the temperature, moisture and expansion ratio of the puffed product to make a sinking feed. The die with the venting port is placed against the template, so it can be used where it is necessary to add vitamins, pigments and flavor enhancers to the puff, avoiding over-aging. The sinking fish feed should contain 10% starch and 12% fat, and the final puffed product contains 10% to 12% water. Excessive drying will cause the sinking feed to float.

The difference between the two kinds of materials produced by the general extruder is mainly in the following aspects:

a, spindle speed

Floating material: The spindle speed is basically at the set speed.

Submerged material: The spindle speed is generally about 1/3 lower than the floating material speed.

b, degree of ripening, degree of expansion

Floating material: more than 95% of the basic full ripening, the degree of expansion is generally between 1.5-2.0

Submerged material: about 80% of the ripening, the degree of expansion is generally not more than 1.3 times.

c. After the material enters the machine, the sinking material will have a more pressure relief process than the floating material, and then the mold will be released, and the pressure inside the barrel will be low.

Floating material: conveying forward, melting and ripening, extrusion molding

Submerged material: transport advancement, melt ripening, pressure relief transport, compression density die (slightly puffed)

d, quenching and tempering water, sinking material should be significantly higher. The tempering moisture of the two materials is

Floating material: about 24%

Shen material: about 30%

e, the template opening rate is different

Floating material: the assumption is generally (1)

Submerged material: approximately (2-2.5)

f, different formulas

Floating material: the amount of starch is generally 20%-25%, the material should float, mainly relying on the expansion of starch.

Submerged material: generally about 10%, it is difficult to sink completely when it reaches 15% or more. The main function is to bond and improve water resistance.

The advantage of the expanded material is firstly to improve the digestion and utilization of the feed. This is because the process of puffing processing requires finer pulverization of the raw materials, and the high temperature puffing process can improve the maturation degree of the starch, which is beneficial to the digestion and absorption of the feed by the fish; secondly, the water stabilization time of the expanded material is long, up to 12-36 Hours, and easy to visually observe and control the feeding of fish, reduce the pollution of water; again, the high temperature and high humidity of the moment can also kill the harmful bacteria in the raw materials.

The key to abundance of aquatic products: 1 suitable technology, high-quality equipment, 2 high-level operation technicians 3 high-quality templates, cutting knives and other related accessories