During the rice hull conveying system, rice hull drag chain conveyor is at the front of the conveying system, mainly used to lift the rice hull from the unloading point to the vibration screen’s feeding point. Because the small density of rice hull, large friction coefficient, mixed with a lot of impurities, such as dust, pull, rice straw, etc. In the actually applicance, rice hull drag chain conveyor has the features of ordinary drag chain conveyor irreplaceable. 1. Mainly design point
Rice hull be conveyed to the feeding port of drag chain conveyor by the belt conveyor, the feeding port be installed at the first intermadiate section casing of the tail section. The chain of drag chain conveyor is driven by the sprocket at head and tail. The rice hull in drag chain conveyor moving with the scraper chain, and lifting to the vibration screen.
1.1 Inclination angle
The rice hull is hard hull, sharp shape, large friction coefficient, and its static angle is more than 45。, so, inclination anle of the L-shaped drag chain conveyor should be the range of 30~40. Large inclination angle can shorted the horizontal conveying length, and reduce the space and equipment cost.
1.2 Scraper chain
1.2.1 Structure and installation form of scraper chain
Scraper chain is the important spare part of drag chain conveyor, which consists of scraper and chain. During the operating, it is driven by the head wheel at the head of drag chain conveyor. Scraper adopts the material of HMWPE. The structure of scraper is blind ram, which connected to the pin link plate of bushroller chain by bolts. The chain adopts the imporved roller chain. The pin roller chain be designed to L-sharped, the bend of L-sharped be fixed with scraper. Because the scraper and guide rail are made of HMWPE, light weight, wear resisting. The guide rail be fixed on the transverse supporting bar
1.2.2 The speed of Chain
The important thing in make wine industry is that keeping the completeness of rice hull during the conveying process. If the drag chain conveyor's chain speed is too fast, on the one hand, the friction between rice hull and closed trough shell will increase, the flow steady of rice hull will be damaged. As a result, a lot of broken rice hull be producted. On the other hand, due to the loose accumulation of rice hull itself, in the process of the scraper pushing the rice husk upward, high-speed movement will increase the pressure of the scraper on the rice hull, the rice hull is easy to be squeezed into a group, the unloading of rice hull is not beneficial. In addition, as the unloading point of rice hull is an open field, when the rice hull are affected by rain and become damp, the friction coefficient between the rice hull will increase, which is more likely to agglomerate, increase the operating load of the scraper, and make unloading difficult. Overall analysis shows that the linear velocity of the chain should not be too high, and its value range should be 0.08 ~ 0.20 m/s. At the same time, under the premise of satisfying the linear speed of the chain, the motor with large output torque should be selected to prevent the phenomenon of insufficient driving force due to the compression of rice hull into blocks.
1.2.Scraper chain Cleaning
The shape of rice hull is sharp and the friction coefficient is large. During the operation of the scraper chain, impurities such as rice hull and rope are easy to be clamped in the gap of the chain and accumulate on the top of the scraper chain. In order to avoid the bad occlusion between the head wheel and the chain caused by the inclusions in the chain and the residual accumulation in the head, it is necessary to add the cleaning device of the scraper chain. The cleaning device is a brush or soft rubber plate, which is fixed above the place where the chain is about to be wound into the head wheel, and is in contact with the top of the scraper chain. When the chain moves under the cleaning device, the cleaning device can sweep the residual material at the top of the chain.