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    Home > Active Ingredient News > Drugs Articles > The concept of superfine pulverizer and the selection of pulverizer

    The concept of superfine pulverizer and the selection of pulverizer

    • Last Update: 2014-11-03
    • Source: Internet
    • Author: User
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    Superfine grinding technology is a new technology developed in the world in the past 20 years The so-called ultra-fine comminution refers to the use of mechanical or hydrodynamic methods to overcome the internal cohesion of the solid so that it can be broken, so as to comminute more than 3 mm of material particles to 10-25 μ M the operation technology is a high-tech material processing technology produced after the 1970s to adapt to the development of modern high-tech Superfine powder is the final product of Zui, which has special physical and chemical properties, such as good solubility, dispersion, adsorption, chemical reaction activity and so on Therefore, ultrafine powder has been widely used in food, chemical industry, medicine, cosmetics, pesticides, dyes, coatings, electronics, aerospace and many other fields The ultra-fine comminution technology of high speed and low temperature comminution adopts supersonic air flow comminution, cold pulp comminution and other methods, which is totally different from the previous pure mechanical comminution methods In the process of crushing, there will be no local overheating, and even crushing can be carried out at low temperature, which is fast and can be completed in an instant Therefore, Zui can retain the bioactive components of the powder to a large extent, so as to make the required high-quality products The particle size is fine and the distribution is uniform Because of the supersonic air flow, the distribution of the force on the raw material is quite uniform The setting of the classification system not only strictly limits the large particles, avoids over crushing, and obtains the ultrafine powder with uniform particle size distribution, but also increases the specific surface area of the ultrafine powder to a large extent, so that the adsorption and solubility are also increased accordingly After superfine comminution, superfine powder with near nanometer particle size can be directly used in preparation production However, the products of conventional comminution still need some intermediate links to meet the requirements of direct production, which is likely to cause waste of raw materials Therefore, the technology is especially suitable for the grinding of precious raw materials To reduce pollution, superfine grinding is carried out in a closed system, which not only avoids the pollution of the surrounding environment by superfine powder, but also prevents the dust in the air from polluting the products Therefore, the application of this technology in food and health care products can control the microbial content and dust Grinding method grinding grinding grinding grinding is a process of material particle grinding by means of the forces of grinding medium (grinding medium) generated with motion; medium impact, and non medium impact; medium impact bending, extrusion and shearing Grinding and friction are the main processes of grinding, that is, extrusion and shearing Its effect depends on the size, shape, proportion, movement mode, filling rate of the material and the mechanical characteristics of the material There are three kinds of typical grinding equipment: ball mill, agitation mill and vibration mill The ball mill is a traditional equipment for ultra-fine grinding, and the particle size of the product can reach 20-40 microns When the particle size of the product is less than 20 μ m, the efficiency is low, the energy consumption is large, and the processing time is long Agitation mill is developed on the basis of ball mill, which is mainly composed of grinding vessel agitator, disperser, separator and delivery pump Under the centrifugal force produced by the high-speed rotation of the disperser, the abrasive medium and particle slurry are grinded, and the middle striking shearing, friction and extrusion are produced on the inner wall of the middle exhaust device to crush the particles The average particle size Zui of the finished product is as small as several microns Vibration mill is produced by high frequency vibration of grinding medium; the particles are crushed by medium impact shearing, friction and extrusion, and the average particle size of the finished product can be less than 2-3 μ m, and the grinding efficiency is much higher than that of ball mill, and the processing capacity is more than 10 times of that of ball mill of the same capacity The air flow type ultra-fine grinding air flow mill can be used for ultra-fine grinding It uses compressed air or superheated steam as the carrier of particles, and the supersonic and high turbulence air flow generated through the nozzle The impact backlog, friction and shear occur between particles or between particles and fixed plates, so as to achieve the purpose of grinding Since the birth of the U.S industrial air flow pulverizer in 1940s, there are six types of air flow pulverizers: disc type, circular tube type, target type, collision type, rotary impact type and fluidized bed type Compared with the ordinary mechanical ultra-fine pulverizer, the air flow pulverizer can pulverize the product very fine (the fineness of the powder can reach 2-40 μ m), and the particle size distribution range is narrower, that is, the particle size is more uniform Because the gas expands at the nozzle and cools down, there is no associated heat in the comminution process, so the comminution temperature rise is very low This characteristic is very important for the ultrafine grinding of materials with low melting point and heat sensitivity However, the energy consumption of air flow comminution is large, and the energy utilization rate is only about 2%, which is generally considered to be several times higher than other comminution methods It is worth pointing out that it is generally believed that the particle size of the product is directly proportional to the feeding speed, that is, the larger the feeding speed is, the larger the particle size of the product is When the feeding speed or the particle concentration in the crusher reaches a certain value, this statement is reasonable Because the feeding speed increases, the particle concentration in the crusher also increases, resulting in particle crowding, and even particle flow like a plunger Only the particles at the front of the plunger can have an effective collision, and the particles at the back can only have low-speed collision, friction and heating with each other However, this is not to say that the smaller the particle concentration is, the smaller the product particle size is, or the higher the grinding efficiency is On the contrary, when the particle concentration is low to a certain extent, there will be no chance of collision between particles and reduce the crushing efficiency Mechanical shear is the most of the existing methods of ultrafine comminution For materials with high brittleness and low toughness, these methods are always effective However, based on the development of deep processing of agricultural products, especially the crushing of high fiber materials (mostly tough materials and flexible materials) with fresh or high water content Zui, the effect of air impact crushing is not good, which is reflected in the large particle size of products, high energy consumption, and the appropriate shear type for crushing such materials Although there are many methods of ultra-fine comminution, the air flow ultra-fine comminution method is widely used in food processing at present People's living standards are constantly improving, and people are paying more and more attention to the requirements of food This puts forward higher requirements for the processing technology of food, not only to ensure good taste of food, but also to ensure that the nutrients are not destroyed, and also to be more conducive to the absorption of human body According to its characteristics, superfine comminution technology can be used in the field of food processing, just to achieve some of the above effects The superfine treatment of food particles can double the specific surface area, improve the activity and absorption rate of some components, and make the surface charge and viscosity of food change wonderfully The application of food processing industry the utilization of food resources includes wheat bran, oat bran, corn bran, corn germ dregs, soybean bran, rice bran, beet dregs and bagasse, which are rich in vitamins, microelements, etc., and have good nutritional value However, due to the large size of the conventional fiber, it affects the taste of food, which makes it difficult for consumers to accept Through the micronization of fiber, it can obviously improve the taste and absorption of fiber food, so that the food resources can be fully utilized and the nutrition of food can be enriched The pericarp and core can be transformed into food by ultra-fine grinding Vegetables are ground into micro paste powder at low temperature, which not only preserves all nutrients, but also increases water solubility due to micro refinement of fiber, so the taste is better The inedible parts of some animals and plants, such as bone, shell (such as eggshell), shrimp skin, etc., can also become calcium source and chitin which are easily absorbed and utilized by human body through ultra-fine treatment The fresh bones of all kinds of livestock and poultry are rich in protein, fat, phospholipid and phosphoprotein, which can promote the development of children's brain and nerves, and have the effect of strengthening the brain and increasing intelligence Fresh bone contains collagen (amino acid), chondroitin, etc., which can moisturize skin and prevent aging Fresh bone also contains vitamin A, B, B2, B12 and other nutrients The content of calcium and iron in fresh bone is also very high, for example, pig bone contains complex calcium phosphate, lipid, protein and other major components Generally, the fresh bone is boiled and eaten after boiling In fact, the nutrients of the fresh bone are not absorbed by the human body, resulting in waste of resources Using the air flow ultra-fine comminution technology, the fresh bone is comminuted into ultra-fine bone paste or dehydrated into bone powder, which can not only keep more than 95% nutrients, but also can be directly absorbed and utilized by human body, the absorption rate can reach more than 90% Bone is a large by-product of meat factory, which is mostly sold at a low price Therefore, making bone into calcium rich products has both nutritional and economic significance In addition, the traditional tea drinking method is to brew tea with boiling water, but the human body does not fully absorb all the nutrients of tea Some insoluble or insoluble ingredients, such as vitamin A, K, e and most of the proteins, carbohydrates, carotene and some minerals, are largely retained in the tea residue, which greatly affects the nutritional and health care functions of tea If the tea is made into powder tea under normal temperature and dry state, and the particle size of the powder is less than 5 μ m, then all the nutrients of the tea are easily absorbed by the stomach and intestines of the human body When the tea is washed with water, it will become a solution without precipitation New functional food or additives 1 Fiber food is greedy Cellulose is called "the seventh nutrient" by the modern nutriology circle It can be used as food filler or physiological active substance, and it is an important functional base material food to prevent modern "civilization disease" and balance the dietary structure Therefore, increasing dietary fiber intake is an important measure to improve human health With the help of modern superfine comminution technology, food fiber can be micronized, which can obviously improve the taste and absorption of fiber food 2 Calcium supplement food The micro powder of animal bone, shell and skin is organic calcium, which is easier to be absorbed and utilized than inorganic calcium These organic calcium can be used as additives to make bone meal (mud) series food with high calcium and high iron, which has unique nutritional and health care functions, so it is known as "functional food in the 21st century" When the particle size of organic calcium powder (including pearl powder) is less than 5 microns, it can be used in some calcium deficient foods such as soybean milk 3 Chitin The ultra-fine powder of crab shell, shrimp shell, maggot and pupa can be used as preservative, water holding agent, antioxidant, etc after modification, there are many other functions Changing the traditional technology to improve the quality of food and reduce the cost of production can make some of the food processing or technology have revolutionary changes For example, in the production of instant tea, the traditional method is to extract the effective components from the tea, and then concentrate and dry them to make powder instant tea At present, it only needs one step to obtain the powder tea product by ultra-fine grinding, which not only greatly simplifies the production process, but also greatly reduces the production cost The other is the production of soybean powder The traditional technology is to soak the soybean first, then crush, peel, finely grind, dehydrate and dry it If the technology of superfine grinding by dry method is adopted, the soybean can be directly crushed and superfine to obtain the soybean powder product without water immersion In this way, not only the nutrition of soybean skin is preserved, but also the energy is saved Because the traditional method first adds water, Zui then dehydrates and dries, which wastes a lot of energy The processing of soft drinks is based on the technology of air flow micro comminution The soft drinks that can be developed include powder tea, bean solid drinks, superfine bone powder to prepare calcium rich drinks and instant mung bean essence, etc If the tea is made into tea powder under normal temperature and dry state, the particle size of the powder is less than 5
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