According to statistical analysis, it was found that the crushing rate of bulk corn increased by 2.9 percentage points after it was transported from the awning barn to the granary.Through testing and analysis, it is found that the Z type bucket elevator is one of the main factors of producing crushing before warehousing. When the conveying capacity exceeds 38t/h, the head section returns grain to the tail section seriously, resulting in crushing. The impact between the grain piled up at the bottom of the elevator and the bottom wheel causes the grain breakage rate to increase; When the head of the Z type bucket elevator is centrifugally discharged, the grain impinges on the inner wall of the head cover, causing backflow and breakage,etc.
Facing those problems, we improved the head section, tail section,slide chute and distributor and other parts. The improvement practice as following:
1.Increase the cross section of the discharge port of the head part and slide chute
The smaller cross section of the discharge port of the traditional Z type bucket elevator leads to the smaller cross section area of the matching slide chute and greater flow resistance. When the conveying capacity reaches 35t/h, the head section of the elevator produces the phenomenon of "piling grain", which causes the grain to flow back to the frame; When the capacity reaches 38t/h, a large amount of grain flows back.
Through calculation, when the throughput is 50t/h, the effective cross section area of the slide chute should be greater than 385cm2. We increased the discharge port of the head part to 40cm*40cm, and replaced the discharge slide chute to Ultra-high molecular polyethylene (UHMW-PE) which with 25cm diameter, with smooth inner wall, wear resistance, impact resistance and low flow resistance.
2.Distribution materials to granary via five distribution
In the traditional central reserve granary, the grain is loaded into 4 granaries by one Z type bucket elevator, which is divided into 3 three-pass distributors. In order to reduce intermediate links in the conveying process, a five-pass distributor is now replaced. The guiding mechanism of the distributor is controlled by motor and limit switch. The section area of the distributor inlet is 1200cm2, and the effective sectional area of a single outlet is 625cm2, so there is space for continuous improvement of the capacity.
3.Change the head cover shape
Material discharging in centrifugal way, the distance beween the traditional head section shaft of center and head section cover upside wall and discharge port side wall is small. The impact phenomenon is more serious in the process of discharging the material, now the distance is increased and change to circular arc form, the head section cover dimension also been increased,there is almost no flowback and the chance that grain hits machine head wall is reduced apparently.
4.Improve the tail section feeding chute
In the feeding process of feeding material to the inlet of the Z type bucket elevator, the grain falls from the height, the grain collides with the steel plate on the bottom surface of the feeding slide chute, and the grain falls from the height collides with the grain in the slide chute, thus increasing the grain breakage. Now three isolation plates are set up in the upper and lower distance of the feeding chute, and plastic spacers are added on the impact surface of the isolation plate and the bottom plate, so as to reduce the impact force of grain and steel plate and reduce the grain breakage rate.
Conclusion as following:
Under the premise of constant rotation speed, bucket spacing and bucket size, via improving the head section cover, tail section and slide chute can improve the conveyor capacity significantly, reducing the rate of grain breakage and energy consumption and improve the enterprise economic benefit effectively.