There are many major factors affecting the operation of the extrusion extruder, and these factors are mutually influential, with the relationship between independent variables and dependent variables. Therefore, how to consider the expansion machinery is a more complicated problem. For this reason, the same extrusion extruder must achieve the same quality of product, and different process parameters, ie different operators, can be used to obtain the same product. Therefore, it is not too much to say that the operation of the extrusion extruder is an art. This machine is the one with the highest level of operation in the feed processing plant equipment. In general, the main factors affecting the extrusion extruder are: 1 raw material; 2 extrusion extruder performance; 3 operation. 5, the structure of the conditioner Sterilize Tattoo Needle,Disposable Tattoo Needles,Make Up Needles Danyang Trading Co., Ltd. , http://www.gdtattoomachine.com
These factors mainly affect product quality, product productivity, and operational stability.
Only relevant issues in the performance of raw materials and extrusion extruders are discussed:
(1) Raw materials: As the feed ingredients are composed of dozens of components such as energy, protein, vitamins, trace elements and additives. The main factors affecting the processing performance of the extrusion extruder are energy and protein. The effect of aquaculture is not only related to the energy and protein components, but also to the addition of trace amounts of vitamins, trace elements and additives. Discussions are now on the raw materials of the extrusion extruder affecting the processing properties and the aquaculture performance caused by the processing:
1) There are many types of feed components, and the properties of the materials are different, which affects the quality of the quenching and tempering.
According to the composition of the main body and the nature of the material, it is divided into protein type, starch type, fiber type, fat type, heat type, etc. The raw materials of different characteristics should be selected differently or the process parameters of extrusion extruder operation should be different. . Everyone knows more about this and will not repeat them.
2), water content and fat content of feed
Single screw extrusion extruder When the feed water content can not be greater than 30%, the fat content is not more than 10%, otherwise the single screw can not work normally.
If the water content is greater than 30% and the fat content is greater than 17%, a twin-screw extruder is required.
At the same time, high feed water content is beneficial for feed sterilization, so. In the same quenching and tempering effect, the twin-screw extruder has better feed sterilization effect than the single-screw extruder. See the moisture analysis of the material below for the reason.
The feed has a certain amount of fat to reduce the wear of the screw on the screw and the barrel. Since the twin-screw extruder can be larger than the fat content by more than 17%, for this reason, the twin-screw extruder has a high-fat screw and machine. The wear of the cylinder can be better than that of a single screw.
3), crushing fineness of aquatic feed:
The pulverization fineness of aquatic feed ingredients is mainly the pulverization of energy, protein raw materials and trace elements.
(1), crushing fineness of energy and protein raw materials:
Fish and shrimp feed ingredients crushed fineness commonly used energy, protein raw materials crushed fine fish is about 40 mesh, shrimp 95% through 80 mesh, particle size is 0.237mm. Since the digestive system in the fish is superior to the shrimp body, the current fineness of the fish can meet the breeding requirements. The fineness of the pulverized raw material of the shrimp is still negotiable, and the determination of the fineness of the pulverization should be based on the digestion characteristics of the aquatic animal and the melting state of the powder in the extrusion processing, as long as the tempering and kneading of the extrusion extruder After that, the digestive system of the powder particle size aquatic animal can be adapted, and the particle size of the powder can be melted after the quenching and tempering, and the material can be uniformly extruded from the film hole. It is clear that the comminution particle size is determined by the melting effect, that is, whether starch and protein are completely degraded and has nothing to do with other factors. As long as the tempering and tempering of the extruder is good, the pulverization fineness is fine. However, if the coarse particles are too coarse, the quenching and tempering effect is not good. The material in the feeding section has not yet entered the molten state. The coarser the particle size, the greater the wear of the screw and the barrel, which is safe, reliable, and reduces the excessive coarse particle size of the screw. And the barrel is worn, and the coarse grain size is still not suitable. The standard of pulverization fineness should be determined by the melting and melting properties of the extrusion extruder and the tempering performance of the temper. Get the most economical granularity. If the quenching and tempering performance of the tempering device is good, the energy of the extruder and the pulverizing particle size of the protein feed are about 40 mesh in the fish feed, and the shrimp feed is 60 to 70 mesh. The experience of others needs to understand the conditions under which the experience is formed. What is the difference between himself and himself?
(2), the fineness of the trace elements
The pulverization particle size of trace elements is now discussed: At present, the fineness of various trace elements and other components in the feed mill is mostly around 100 mesh, and the particle size is 0.18 mm. Trace elements are difficult during extrusion
The melting effect is achieved and still appears in the form of particles. For young aquaculture objects, if the particles of each trace element ingested every day should be consistent with the probability error requirement, the minimum number of particles in the feed should not be less than 8-10.
For shrimp, the amount of bait per day should be related to body length. According to the body length of the shrimp, the daily feed amount is: Qe=0.017L1.5g, and L is the body length (cm). According to the body length of the shrimp, the daily feed amount is calculated as follows: body length is 1cm, 2cm, 3cm, 5cm, respectively: 0.017 g, 0.038 g, 0.088 g, 0.19 g.
When the shrimp is 1cm, 2cm, 3cm, 5cm, the particle size of the micro-crushing is calculated: the energy and protein components of the shrimp feed component account for 95-98%. The constant accounts for 2 to 3% (the heat-sensitive components such as vitamins are added after extrusion), and the trace elements (10% of the pre-mixed feeds) account for about 1%.
When the shrimp is 1cm long, the total weight of trace elements in the shrimp is divided into: 0.000017g, 0.000038g, 0.000088g, 0.00019g.
There are 6-8 kinds of trace elements commonly used in shrimp. In order to mix evenly, at least 8-10 capsules should be eaten every day to meet the nutritional error requirements. For this, 1cm, 2cm, 3cm, 5cm The average weight of shrimp per day into each trace element is: 0.00000035g. 0.00000079g, 0.0000018g, 0.00000395g.
The trace elements are copper sulphate (for example, the addition amount is 20 g/t, the mixing ratio is 1:50,000), the copper sulphate has a bulk density of 1 t/m3 = 1 g/cm3, and the maximum pulverized volume of the trace elements is 1 cm per shrimp. Volume of granular trace elements: 0.00035 mm3, 0.00079 mm3, 0.0018 mm3, 0.00395 mm3.
When the shrimps are 2cm, 3cm, and 5cm long, the pulverized particle size of the trace elements should be 0.087 mm, 0.11 mm, 0.15 mm, and 0.196 mm, respectively.
From the above analysis, it can be seen that when the shrimp is less than 3 cm in length, the particle size of the micro-elements is not exactly 100 mesh, and the particle size should be less than 180-200 mesh to meet the requirements. The pulverized particle size of the trace elements with a shrimp length of 3 cm or more has been satisfied at 100 mesh. When the amount of trace elements added is less than 20 g/t, the fineness of 100 mesh is less than the requirement, and must be less than 180 to 200 mesh.
(B), extrusion extruder performance
The extrusion extruder mainly consists of a feeding system, a tempering device, an extrusion and puffing system, a cutter system, a transmission system, a control system, and a machine base. The most important part of the screw and barrel is the main body that determines the performance of the extruder. Since the structural parameters of the screw and barrel of the extrusion extruder are the most critical factors affecting the quality and yield of the extrusion extruder, the processing of different raw materials, the parameters of the screw or the combination of the screws should follow the change to obtain a better extrusion. Puffing effect. However, the performance of the conditioner is also seriously affecting the key to whether the extrusion technology can be fully utilized. It is also an important factor in ensuring the performance of the extruder. As some other experts such as screws and barrels talked about more comprehensively, I will not go into details. Now I will discuss the extrusion effect of the extruder on the tempering machine:
1. Mechanism of feed quenching and tempering: Feed quenching and tempering is the process of feed water heat treatment. The feed quenching and tempering is actually the heat (quality) of the gas phase (steam), liquid phase (water droplets dispersed in fine water), and solid (powder) Material) The process of transferring heat and mass. Steam is both a heat transfer body and a moisture transfer body during the quenching and tempering process of the feed. Moreover, the heat and quality of the feed are constantly changing during the quenching and tempering process, and the quenching and tempering is also a process in which the heat and mass in the steam are transferred to the inside through the outer surface of the powdery particulate material.
The quenching and tempering of the powdery material is that the steam is evenly distributed around the powdery material, and the interface layer is formed near the surface of the granular material. The heat transfer and mass transfer rate of the quenching and tempering process are determined by the internal and interface layers of the steam and powdery granular materials. Temperature gradient, velocity gradient, humidity gradient, material properties (density, particle size, water content) and other factors.
2. Objectives and requirements for quenching and tempering: The feed powder is softened by the action of water and heat during the quenching and tempering process. The softening and softening requirement is that the center of the granular material can be softened to the best, but the target and requirements of quenching and tempering.
4. Feed quenching and tempering process:
When the solid phase powdery material with low temperature and low moisture content enters the conditioner with a certain speed, the steam pressure is reduced from 200kpa~400kpa to normal pressure, and the steam temperature is reduced from 120°C~143°C to 100°C. The process of tempering and ripening of the raw meal is started.
During the quenching and tempering process, the partial pressure of water vapor in the steam is higher than the partial pressure of water vapor on the surface of the powdery granular material. For this reason, the surface of the powdery granular material continuously absorbs the water in the water vapor (see Figure 7 is from 1--- 4 is the process of absorbing water from the material). At this time, the surface moisture of the powdery material is higher than the internal moisture of the material (ie, the humidity gradient). There is a moisture pressure difference between the surface moisture and the internal moisture of the material, and the water pressure difference between the surface moisture and the internal moisture of the material is high, and the law of the water pressure is high to the area where the water pressure is high. . Therefore, the powdery particulate material not only adsorbs moisture on the surface but also transfers to the inside. The powdery granular material achieves the purpose of quenching and tempering under the impacting and turning of the conditioner.
Figure 7 Process of material absorption of water
1) The most commonly used double-cylinder differential conditioner is a combination of high-speed quenching and low-speed heat preservation. Its structure basically conforms to the above-mentioned quenching and tempering, and the quenching and tempering performance is better, but due to the double-tube differential conditioner The structure and process parameters are different and their quenching and tempering effects are still different.
2), the moisture of the material: is an important factor affecting the quenching and tempering effect. Under the same conditions of quenching and tempering temperature and quenching and tempering time, the moisture content of the material is high, and the quenching and tempering effect is better than the material with low moisture, due to the microorganism The resistance to damp heat is poor. Under the action of steam, microorganisms can absorb high temperature water in the surrounding medium, thus promoting the coagulation of microbial cell proteins and accelerating the death of microorganisms (the time of microbial death of damp heat materials is lower water) 1/3 of the material. Therefore, under the condition of high moisture content of the material, the mold and pathogenic bacteria such as Salmonella and the hemagglutinin and protease inhibitors of the plant have high destruction and inactivation, and the degree of starch gelatinization is also high. For this reason, the twin-screw extruder of high material moisture has better damage to harmful factors and inactivation of harmful microorganisms than single-screw extruder.
The above discussion shows that to obtain better extrusion and puffing effect, there are many factors. It is necessary to adjust the screw combination of the extrusion extruder according to the product requirements and the characteristics of the raw materials, control the relevant parameters of the conditioner, and determine the parameters of the quenching and tempering. In order to obtain a better extrusion effect.