The alumina washing project of one of our customers in Guangxi is a newly expanded concentrator. The feeding equipment is heavy duty apron feeder, the specification and model are 1500mm× 24000mm, the feeding capacity is 300tph, and the driving type is driven by hydraulic motor. The on-site process is to evenly transport bauxite with a water content of about 15% to a cylinder washing machine through a heavy plate. The newly designed apron feeder is optimized and improved by investigating the actual application and combining with the specific working conditions.
1 Existing problems
(1) The on-site heavy plate adopts the traditional structure, and the chain plate device is set up to push up the square steel. Due to the large viscosity of the bauxite material, it is difficult to discharge the material, and the chain plate adhesive material returns with the chain plate.
(2) The return roller is designed to be arranged at 600-800mm intervals, but the chain plate between the two return rollers is too large during the actual operation of the production, and the equipment is often "stuffy", and even accidents that damage other parts occur.
(3) The back-up roll is designed to be horizontally arranged in four rows, and the middle two rows cannot reach the design life due to the influence of large water content of the material, and the site working condition is extremely bad, resulting in difficult maintenance.
In view of the problems existing in the production and operation of heavy duty apron feeder, the driving type, chain plate device and support structure of the heavy duty apron were optimized.
In the original design, the square steel on the chain plate of heavy duty apron feeder can reduce the impact of large materials on the heavy plate and extend the service life of the heavy plate, while the bauxite has a small impact on the chain plate due to its large viscosity, small particle size and other factors. After the installation of the square steel, the chain plate structure is easy to accumulate adhesive materials, and the scraping device cannot completely scrape the materials on the chain plate. Now the chain plate structure is improved to a flat structure, the square steel on the chain plate in the original design is removed, and the rubber sheet scraping device installed under the head of the heavy plate is also improved, so that the chain plate on the return journey, the adhesive material is scraped by the scraping device, and the material is collected through the hopper 2-3]. In the original design, the return roller adopts 600~800mm interval arrangement, and the middle distance of the return roller is improved to 400mm, which reduces the distance between the return roller, prevents the chain plate from hanging too large, reduces friction, and prevents the occurrence of "stuffy car" accidents. The original design of the back-up roll adopts four rows of horizontal layout to facilitate the maintenance and replacement of the support roll, but due to the high water content of the on-site material, the support roll is eroded by water leakage for a long time, affecting the service life. Now the support structure of the chain plate is changed to the type of hollow shaft through the length roller. In the past, the type of the bearing seat of the through the length roller is cast aluminum bronze bearing bushing, which has poor lubrication effect on site, resulting in increased power consumption and even problems such as the back-up roller does not turn.
In this design, apart from the effective width of the bearing seat chain plate of heavy duty apron feeder, the integral bearing seat aligning roller bearing is adopted, which basically eliminates the influence of the chain plate leakage on the bearing lubrication. The hollow shaft length roller makes the middle two rows of support rollers without bearing structure, and the problem of service life reduction caused by the middle support roller can not be maintained has been successfully solved. The driving mode is improved to hydraulic motor drive, which has the advantages of stepless speed regulation, small space and easy process control. The biggest feature of hydraulic drive is suitable for low speed and heavy load environment. The hydraulic transmission system works stably and brings little wear to the transmission system, thus improving the reliability and service life of the system. Perfect protection system, easy to maintain and operate. Hydraulic power station is provided with protection points, including oil pressure protection, filter blockage protection, oil level protection. As long as the hydraulic oil and cooling water are normally provided to the system, the maintenance workload of the system is very small. The transmission arrangement of hydraulic drive mode is more flexible, and the low-speed end of the motor adopts the keyless and non-foundation installation mode of hollow shaft locking disc and torque arm, which can protect the drive shaft to a greater extent and save installation space. The maintenance is simple, the hydraulic oil is changed once a year, and the drive device is rarely stopped for maintenance.
After the structure improvement of the equipment, the adhesive phenomenon of heavy duty apron feeder is obviously controlled, and the problem of material adhesion is well solved with the scraping system. Reduce the middle distance of the return roller, and the "stuffy car" accident does not happen again; The life of intermediate support roll is obviously improved. The equipment has been running so far, the use effect is good, and many problems existing in the original design structure have been greatly improved.
