device

A drum classifier is a classifier used by mineral processing plants to form a closed working system with the same grinding machine. It requires a mechanism for transporting and settling sand, so this type of drum classifier is called a mechanical classifier. In fact, the classification process is carried out based on the different settling speeds of particles.

In addition to being mainly used as auxiliary equipment for grinding, drum classifiers are sometimes also used for washing, desliming, and dehydration of muddy ores. Three drum classifier can be divided into spiral classifier, rake classifier, floating groove classifier, etc. according to different conveying methods.

Due to the simple structure and convenient operation of the drum classification mechanism, as well as the large inclination angle of the classification groove, it is easy to connect with the grinding machine for gravity flow, so it is widely used. Other types of classifiers, although still in use in China, have ceased production.

The appearance of the three drum classifier is a rectangular inclined groove, with a bottom inclination of 12-18.5 meters and a semicircular bottom. There are 1 or 2 longitudinal shafts installed in the groove, and spiral blades are continuously placed along the shaft length. Use the upper transmission mechanism to drive the spiral shaft to rotate. If it is a double helix, the spiral blades rotate outward when viewed from above. The slurry is supplied from the side of the tank. Form a settlement grading surface at the bottom of the trough. The coarse particles of the three drum classifier sink into the bottom of the groove and are pushed upwards by a screw, causing dehydration during transportation. Non settling fine particles are discharged from the surface slurry flow zone through overflow weirs. The grading process of the mud hopper is basically the same as that of the mud hopper. A three drum classifier has one located below the grading groove. The upper crossbeam of the frame is equipped with a lifting device to adjust the distance between the spiral blades and the groove bottom. When parking, the spiral shaft is raised to prevent mineral sand from depositing and burying on the spiral blades.

The height of the liquid level in the drum classifier can be divided into high weir type and immersion type (also known as sinking type). The overflow weir of the high weir drum classifier is higher than the center of the lower spiral shaft and lower than the spiral cascade. The length of the stratified liquid surface is not large, and the liquid surface can directly feel the agitation on the spiral blades, making it suitable for coarse grading, with grading particle sizes mostly above 0.15mm. The lower spiral blade is completely immersed in the liquid surface, with a large and stable grading area, suitable for fine-grained grading, with a grading particle size below 0.15mm. Its overflow productivity is relatively high. In addition, there is a low weir type drum classifier, which has a lower classification liquid level than the lower spiral bearing, a very small liquid level, and a strong stirring effect. It is mainly used to wash muddy sand and gravel.