The analysis of the leakage of mineral powder and material
In the running process of z type bucket elevator, many buckets of z type bucket elevator are in accordance with a specific speed, fill the bucket with powder and material from the bottom. During the charging operation, the bucket is always in the state of extruding the mine powder and material, sometimes there will also be extrusion housing. To achieve the purpose of ensuring the continuity of hopper loading and the bucket can be filled, it is necessary to have powder or material layer with specified height, so as to ensure that the driven shaft of z type bucket elevator is always in the protection of the powder or material. The extruded mineral powder and material continue to flow into the packing cup on both sides of the housing. Considering that the packing needs to fix the surface of the shaft and ensure that it is in a stable state according to the certain force, it will cause wear and tear of the mine powder at the rotating shaft neck section to varying degrees, thus leading to the appearance of the gap between the shaft and the packing, so that the mine powder and material leak out from the worn shaft neck section. And because the powder and material by the extrusion is mostly continuous, resulting in the powder and material will continue to rotate with the driven shaft by the sealing leakage.

Features of the new sealing structure
Considering the disadvantages of packing sealing structure and the unscientific nature of the type selection of driven shaft sealing structure, through the study of many forms of sealing structure in China, in addition, also with reference to the selection of materials and the degree of difficulty in machining, the new sealing structure of z type bucket elevator has the following advantages. First, to ensure the compact structure, especially in the process of dealing with small axial space, which can get more convenient and simple installation. Second, the new sealing structure is relatively simple, and to a large extent to facilitate the processing of machinery. Third, the gland needs to be rotated with the axis by means of the set screw, and the packing in the pressure bowl is in contact with the surface of the driven shaft. At this time, both of them are in a relatively static state. After the mineral powder or material penetrates the gland, the gap between the packing and the shaft is needed to be able to flow out. Considering that there is no obvious relative motion between the shaft and the packing, the mineral powder or material cannot flow out of the gap, so the surface of the shaft will not be worn by the mineral powder or material. Four, the compaction degree of the packing between the gland and the packing box needs to be adjusted conveniently and simply with the help of the setting screw. In the process of leakage of mineral powder or material, only a little wear will occur on the groove surface and between the packing, but no significant wear will occur at other locations. Five, the screw parts of gland is installed in the cylinder end of the packing box, in the case of gland rotation with shaft, the mineral powder or material that is forced into a spiral is thrown in the opposite direction. In this process, only a small amount of ore or material is spiraled into the feeding port, which will largely ensure an effective reduction in the amount of ore powder or other materials being released.
The analysis of economic benefit
1.After the modification of the sealing structure of z type bucket elevator, the phenomenon of frequent change of packing and driven shaft was completely eliminated. This greatly reduces the amount of labor of operators and maintenance personnel, thus achieving the effect of saving costs.
2.Before the modification of the sealing structure of z type bucket elevator, it is necessary to replace several driven shafts, packing cups and lubricating equipment every year, which will lead to the contamination of materials due to oil leakage to a large extent. Because no suitable vertical conveying device was found at that time, after modification，the cost of spare parts and materials would be greatly reduced, thus effectively reducing the maintenance cost.
3.In recent years, the vast majority of companies and enterprises in China are using z type bucket elevator, but the improvement of sealing structure is not much. If the realization of its transformation, which will not only extend the service life of z type bucket elevator, but also can reduce the cost of production, improve the economic benefits of enterprises and companies.