Flaking is the process of rolling the oil from granular to sheet using the extrusion action of machinery. The purpose of flaking is to destroy the cell tissue of the oil, increase the surface area of the oil, shorten the distance of oil outflow, which is conducive to the extraction of oil and improving the effect of steaming. The requirements for rolling blanks are that the blanks are thin and uniform, the powder degree is small, and there is no oil leakage.
1.Why do we need to flake? Oilseed kernels are composed of countless cells. The surface of oil cells is a relatively tough cell wall composed of cellulose and hemicellulose. Oil and other tissues are contained in the cell wall. To extract oil from the cell, it must destroy the cell wall on its surface and destroy the cell structure of the oil. When flaking, the compression action of mechanical external force can be used to destroy the cell tissue of the oil and the cell wall of some cells. The thinner the oil is rolled, the more cell tissue is destroyed, and the better the oil extraction effect
2. Factors affecting the flaking effect The factors that have a great impact on the flaking effect are mainly the properties of the oil, namely oil content, water content, shell content, impurity content, particle size, temperature and plasticity, etc. The type of equipment and the operation level of personnel are also important influencing factors.
The oil entering the flaking machine must be strictly removed from impurities and must not contain hard impurities, especially metal impurities, otherwise these hard impurities will cause damage to the surface of the roller and even cause serious accidents of the flaker falling off. Oil that has not been strictly cleared and removed shall not be directly sent into the rolling machine. Magnets are installed at the feed port of the flaker machine, which is specially used to adsorb magnetic impurities. Operators should frequently check the adsorption of these magnets to prevent the magnetic impurities on the surface of the magnet from being cleaned up in time, resulting in hard impurities such as iron impurities in the materials entering the rolling mill and damaging the surface of the roller.
The grain size of the oil must meet the requirements of flaker and ensure that the rolling roller has a small enough intling angle. At the same time, the grain size of the oil is uniform and consistent to ensure the basic uniformity of the billet after rolling. For large-grained oil, it must be properly crushed and softened before rolling the billet, so that its mechanical properties meet the best requirements of the rolled billet.
In the process of flaking, the oil is deformed by the external force of the roller, and the ability of the oil to resist the external force changes with the moisture of the oil. Dried oilseed has significant brittleness, and there are many cracks on the rolled blanks, which are easy to crush with a little pressure. Wet oilseeds have great plasticity and are easy to form flakes when squeezed. When the water content of oilseed is high, part of the oil will be separated under the action of the roller to make the blanks bond, forming a very thin strip. When the moisture content of oilseed is very high, oil will be released under the action of the roller, which will reduce the friction between the oil and the roller, and even stop the rolling operation.
The ability of oil to resist external forces also changes with temperature. The lower the temperature, the greater the elasticity of the oil and the smaller the plasticity. On the contrary, the greater the plasticity. As the temperature increases, the plasticity of the oil increases, and the viscosity of the oil contained in it decreases, making it easier for oil to come out when rolling billets. The oil content of the oil has a great impact on the quality of the rolled billet. When the billet is rolled, the oil is pressed out by the pressure of the roller, and the oil is squeezed out and attached to the surface of the new billet. When the oil content of the oil is very high and the blank is rolled very thinly, a large amount of oil is squeezed out to lubricate the roller surface, which reduces the yield of the rolling mill and even makes it impossible to work.
The oil contains more hard shells. When rolling blanks, the gap between the rollers will be enlarged due to the high ability of the shell to resist external forces, resulting in the reduction of the quality of the rolling billet or the instability of the quality. At the production site, if you hear the impact of the roller, it is basically caused by a large number of impurities in the oil. These impurities are sometimes shells from the bottom of the warehouse (the oil will be graded during the flow out of the warehouse, and a large number of impurities such as straw and shells will come out at the end), etc. It is also possible that the dust attached to the surface of the equipment will fall off after clumping. These impurities enter the rolling mill and increase the gap between the rollers. At this time, the rolled blanks The thickness increases. When these impurities pass through, the roller will quickly narrow the gap and make a collision sound. At this time, the rolled blank is thin and powdery.
When the roller runs for a period of time, there will be wear and tear, and the roller needs to be ground. Grinding rollers is also a technical job. It not only smoothes the surface, but also has many skills and requirements. I have no training in this field and no experience in grinding rollers, so I won’t say more here. Grinding rollers needs to be ground by professional manufacturers or trained professionals. Operators should strengthen the inspection of daily production, especially to check whether the thickness of the blank is appropriate and whether there is any leakage. When the thickness of the blank is not suitable, it is necessary to adjust the pressure at both ends of the roller in time to make the thickness of the blank meet the production requirements of the later process. If any leakage is found, it should be stopped in time to check the cause of the leakage and solve it, so as to prevent the oil that has not been rolled into the next process.
