The white material of the horizontal rice milling machine enters the white room from one end and flows out from the other end of the white room. Under the action of the high-speed rotating roller, the rice grains are ground white in the flowing state. The motion of the rice fluid in the white roller can be regarded as a horizontal spiral around the roller. The flow direction of the rice flow in the white roller chamber is perpendicular to the gravity direction of the rice flow. This type of rice mill has the following technological characteristics:
1.1 Good White Uniformity The white uniformity of rice grains is related to the structure form of the roller, the material of the roller surface, the motion parameters of the roller, and more importantly, the motion state of the rice grains in the white chamber. Rice grain white in rolling, its white uniformity is the best. In the horizontal rice mill, the motion of rice grains in the white roller is obtained from the roller. Under the action of the high-speed rotating roller, the rice grains roll sharply. The rice grains both roll along its long axis and turn over along its short axis (see Figure 1). The rice grains are in a state of irregular and rapid rolling motion in the white roller room. It is this irregular sharp tumbling that makes every point of the rice grain have the opportunity to be rubbed off by grinding and achieve a good effect of uniform grinding white.
1.2 Broken rice is easy to be produced in the process of grinding white
In the process of white grinding, influenced by the gravity of the rice fluid itself, the density of the rice fluid in the cross-section of the white grinding chamber is uneven. The density of the rice fluid in the lower part of the white grinding chamber is high, while the density in the upper part is low. Therefore, in the lower part of the white grinding chamber, the rice grains are subjected to great grinding pressure, which is easy to produce broken rice. In the upper part of the white grinding chamber, due to the small density of rice grains and the large gap between rice grains, the rapid collision between the rice grains and the components of the white grinding chamber under the action of the high-speed rotating roller is also easy to produce broken rice.
In the design of a horizontal rice milling machine, it is required that the rolled rice husks should be discharged from the bran sifter in a 360° circle towards the grinding chamber. In the process of production, due to the gradual accumulation of rice bran discharged in the process of grinding, the screen holes are blocked or the screen size is reduced, and the effective bran discharging area is smaller than the designed bran discharging area. In the process of production, the bran discharging screen surface is often not cleaned in time, resulting in the rice husk under the grinding can not be discharged from the grinding room in time, and the rice contains more bran powder. Of course, the bran removal of horizontal air jet rice mills does not exist in the above phenomenon. If in production, before and after the shift, the operator strengthens the cleaning of the bran sieve, can solve the problem.
According to different feeding and discharging modes, vertical rice milling machines can be divided into two kinds: vertical rice milling machines with top feeding and bottom discharging and vertical rice milling machines with bottom feeding and top discharging, which are discussed separately below.
2.1 The white material of the vertical rice mill enters the white room from the top of the rice mill. Under the combined action of the roller and the gravity of the rice fluid, the rice is white in the flow and discharged from the lower part of the white room. The motion of the rice fluid in the white roller can be regarded as a vertical spiral from top to bottom around the roller. The direction of the rice flow in the grinding chamber is the same as that of its own gravity. The machine shows the following technological characteristics:
2.1.1 Low power consumption in the rice milling process, rice fluid moves from top to bottom. Affected by gravity, the rice grains have the ability to transport themselves from top to bottom, thus reducing the power consumption of the rice machine. The power consumed by the roller in the rice mill is mainly used for the white rolling of rice grains. Unlike horizontal rice mills and vertical rice mills with lower feed and upper discharge, the power consumed in the rice roller is not only used for white grinding of rice grains, but also for axial conveying of rice grains.
2.1.2 Less broken rice produced in the process of grinding white, in the process of grinding white, the rice grain fluid density on the cross-section of the machine grinding white room is uniform, so the white grinding pressure is uniform, producing less broken rice, produced less broken rice, rice bran discharged pure. Compared with the horizontal rice roller, the rice bran is basically no small broken rice, and the content of the millet rotary is very small. A separate chaff separation process may be considered in production.
2.1.3 Less Bran in rice Discharging machine The grinding chamber of this machine is in a vertical state, so the discharged rice bran will not pile up on the bran discharging sieve plate and block the sieve hole of the bran discharging rice sieve as in the case of horizontal rice milling machine. The effective bran discharging area of the rice machine is equal to the designed bran discharging area. The rice husks under the grinding process can be discharged from the grinding room in time, and the rice out of the machine contains less bran powder. Less bran powder in the rice is conducive to reducing the load of the rice machine, reducing the crushing of the rice machine, and improving the finish of the rice grains.
2.1.4 If the uniformity of white grinding is slightly poor, the self-gravity of rice fluid in the white grinding room is adopted to speed up the speed of rice passing through the white grinding room. When the same structural parameters and motion parameters of the roller are used as those of the horizontal rice mill, the grinding time of the rice grains in the machine is shorter because of gravity than that of the horizontal rice mill, and the grinding action of the rice grains is slightly weaker. The rolling times of rice grains in the process of white grinding are also relatively reduced, and the uniformity of white grinding is slightly worse than that of horizontal rice milling machines. In production, multi-channel white grinding can be used to improve the uniformity of white grinding. 4 or 5-channel white grinding is the best, which can not only ensure good uniformity of white grinding but also can be multi-machine light grinding to reduce broken rice.
2.2 Bottom feed and top discharge vertical rice milling machine White material enters the white milling chamber through the lower part of the rice milling machine, and the rice grains are white in the flow and discharged from the upper part of the white milling chamber. The motion of the rice fluid in the white roller can be regarded as a vertical spiral from the bottom up around the rice roller. The direction of the flow of rice fluid in the grinding chamber is opposite to the direction of its own gravity. This machine has the following technological characteristics.
2.2.1 Reducing lifting equipment and simplifying process Because the machine is discharging from the top and feeding from the bottom, when multi-channel white grinding is adopted, the discharging port of the front rice milling machine can be connected with the feeding port of the back rice milling machine, which can eliminate the lifting machine usually used between the two rice milling machines and simplify the production process. The front and back roads are directly connected with the rice mill, and the flow rate is stable during production, which reduces the instability of the rice mill flow caused by slippage and material blocking of the hoist, and is conducive to improving the effect of rice milling technology. The winnowing hopper of the hoist is easy to wear, and its maintenance work is a very heavy task. Reducing the elevator can reduce the one-time equipment investment and equipment maintenance and management costs.
2.2.2 Less Bran Powder in rice Discharging machine The grinding chamber of the machine is vertical, and there is no accumulation of rice bran on the bran discharging sieve plate. The discharging rice is less bran powder, the same as the vertical rice milling machine with top feed and bottom discharge.
2.2.3 The uniformity of rolling white should be good, and attention should be paid to avoid over-rolling. In the rolling production, the rolling roll should overcome the gravity of the rice fluid to transport the rice from bottom to up. Under the influence of gravity, the speed of rice running from bottom to top is slower. Compared with horizontal rice milling machines and vertical rice milling machines with top feed and bottom discharge, the time of rice grinding in this machine is longer, and the number of turning of rice in the process of grinding is correspondingly increased, so the uniformity of rice grinding is better. If the operation is not proper, it is also easy to cause rice grain to over and broken rice increase. The design of a reasonable roller structure, the selection of appropriate roller motion parameters and the regulation of flow rate can achieve better uniformity of rolling white while avoiding over-rolling and crushing of rice grains. 2.2.4 The power consumption of the meter machine is high. In the process of grinding white, the rice grains must overcome their own gravity to run from the bottom up. The motion of the rice grains is obtained from the roller. The power consumed by the rice mill on the roller is not only used to grind the rice grains but also to overcome the gravity of the rice flow to transport the rice grains from the low end of the white chamber to the high end. The power consumption of this type of rice machine is higher than that of vertical rice machines and horizontal rice machines.
Source:
Online/GFMM
Comment Now